Leptin and nitric oxide (NO) are both important messengers in intra- and intercellular communication systems in vertebrates. Several studies have demonstrated an involvement of both substances in the immune response. Here we tested the effects of chronic leptin and anti-leptin treatments on the NO production and phytohaemagglutinin- (PHA) induced cutaneous inflammatory response in a wild passerine, the greenfinch (Carduelis chloris). Plasma leptin levels of individual birds were consistent in time but could be still temporarily increased by administration of recombinant chicken leptin. Increase of plasma leptin was also induced by administration of anti-leptin, which can be most likely explained by increased endogenous leptin production due to disruption of signalling pathways. Contrary to previous findings in mammals, leptin administration reduced systemic NO production. Leptin increased cutaneous swelling response to PHA. This immune-enhancing effect was observable despite the similar plasma ...
Leptin is a type I cytokine and belongs to the long-chain helical cytokine subfamily just as GH, IL-6 and G-CSF. Leptin is produced mainly in white adipose tissue and thereby reflects body energy stores. Leptin serum concentrations are high in obese and low in underweight individuals or in those with low body fat e.g. in athletes and in patients with lipodystrophy. The leptin/leptin receptor system is crucial for the regulation of body weight. Rare homozygous mutations in the leptin gene can lead to defects in synthesis and/or secretion of leptin resulting in congenital leptin deficiency with low or undetectable serum levels of leptin. Affected children show an insatiable appetite and food seeking behaviour, excessive weight gain and a multitude of metabolic and hormonal disturbances including hypogonadotropic hypogonadism. Patients can be effectively treated by substitution with recombinant human leptin (metreleptin). Recently, we have described mutations in the leptin gene which result in ...
Leptin is an important regulator of insulin action; both leptin deficiency and leptin resistance are associated with insulin-resistant glucose metabolism (4,12). Furthermore, leptin replacement improves insulin sensitivity in subjects with leptin deficiency (5-8). Part of the beneficial effect of leptin replacement therapy could be a result of reductions in body weight in both leptin-deficient rodents and rodents with high-fat diet-induced obesity (3,11,15). However, leptin therapy increases insulin sensitivity in the absence of a significant decrease in body weight or causes a greater reduction in blood glucose concentration after leptin-induced weight loss than after weight loss induced by pair-feeding alone in wild-type and leptin-deficient rodent models (1,2,16) and improves insulin sensitivity in leptin-deficient subjects, even in the absence of significant changes in body weight (7,8,17). In contrast, our data demonstrate that increasing leptin availability above normal plasma ...
TY - JOUR. T1 - Effects of growth hormone and pair-feeding on leptin mRNA expression in liver and adipose tissue. AU - Ashwell, C. M.. AU - McMurtry, J. P.. AU - Wang, X. H.. AU - Zhou, Y.. AU - Vasilatos-Younken, R.. PY - 1999/7/1. Y1 - 1999/7/1. N2 - Previous research has reported that elevations in circulating growth hormone (GH) levels in meat-type chickens depresses feed intake (FI) more than 30%. It is known that the product of the obese gene, leptin, functions to regulate FI and energy expenditure. To investigate the effect of GH on leptin gene expression, broiler chickens were infused with recombinant chicken GH. To separate any secondary effects of a GH-induced reduction in FI on leptin expression, groups of birds were pair-fed to an average level of voluntary intake similar to GH-treated birds, but received no GH treatment. GH treatment induced a dose-dependent increase in liver leptin gene expression, as measured by reverse transcriptase-polymerase chain reaction, whereas leptin ...
TY - JOUR. T1 - Central (ICV) leptin injection increases bone formation, bone mineral density, muscle mass, serum IGF-1, and the expression of osteogenic genes in leptin-deficient ob/ob mice. AU - Bartell, Shoshana M.. AU - Rayalam, Srujana. AU - Ambati, Suresh. AU - Gaddam, Dhanunjaya R.. AU - Hartzell, Diane L.. AU - Hamrick, Mark W. AU - She, Jin-Xiong. AU - Della-Fera, Mary Anne. AU - Baile, Clifton A.. PY - 2011/8/1. Y1 - 2011/8/1. N2 - Both central and peripheral leptin administrations reduce body weight, food intake, and adiposity in ob/ob mice. In this study we compared effects of intracerebroventricular (ICV) and subcutaneous (SC) administration of leptin on bone metabolism in the appendicular and axial skeleton and adipose tissue gene expression and determined the effects of ICV leptin on bone marrow gene expression in ob/ob mice. In experiment 1, leptin (1.5 or 0.38μg/d) or control was continuously injected ICV for 12 days. Gene expression analysis of femoral bone marrow stromal ...
Leptin, Weight Loss, and Acupuncture By Dr. Li Zheng Leptin is derived from the Greek word leptos meaning thin. Leptin is one of the key hormones involved in hunger, metabolism, and how fats and carbohydrates get stored and utilized. Leptin tells your hypothalamus that you have eaten enough and need to start burning fat. The hypothalamus is the control center of the brain for fullness and fat storage. The rate of production of leptin directly correlates with weight loss or weight gain. Women have significantly higher circulating leptin than men. Leptin resistance is very similar to insulin resistance. With insulin resistance, chronic elevated levels of insulin make your muscle and fat cells more resistant to the action of insulin. Chronic elevated leptin levels decreases the hypothalamus sensitivity to leptin. If your body produces too much fat by chronically drinking soda and/or eating too much ice cream, the long term elevated leptin will desensitize your hypothalamus. As a result, your ...
INTRODUCTION. Leptin is a hormone produced mainly by the white adipose tissue, with multiple actions in the endocrine and immune systems, including glucose homeostasis, reproduction, bone formation, tissue remodeling and inflammation (1). Leptin is a key regulator of energy homeostasis, by regulating energy intake and expenditure through its actions on the arcuate nucleus of the hypothalamus (2,3). Leptin levels are positively correlated with fat mass, being increased in obesity (4,5). Among mice that are leptin-deficient (ob/ob) or leptin-resistant (db/db), blunted metabolic rate and hyperphagia are characteristic features and obesity is a hallmark feature (6-10). In particular, ob/ob mice also have cellular immune deficiency, hypogonadotropic hypogonadism, hypercortisolism, decreased levels of growth hormone, type 2 diabetes and central hypothyroidism. This phenotype is prevented or even reversed with the administration of exogenous leptin. In humans, leptin deficiency is observed in ...
We found that high levels of leptin were related to increased risks of ischemic heart disease independently of traditional risk factors in men and that this prognostic information also remained significant when carotid IMT and aortic PWV were both included in the Cox regression. Importantly these analyses included BMI as a measure of obesity and this implies that leptin gave additional information independently of the degree of adiposity. This is in line with the idea that leptin resistance, an insensitivity to feedback signaling of adipose stores to the CNS, is linked with increased risk for ischemic heart disease in patients [17]. However, since our study did not include an intervention aimed to affect leptin levels, this does not provide definite proof of causality. Elevated levels of CRP have been suggested to participate in induction of leptin resistance by direct interaction with the leptin molecule [18]. The positive correlation between leptin and CRP in both men and in women in our study ...
An inhibitory effect on leptin synthesis and release has been demonstrated for the catecholamines, NE and epinephrine, and for isoprenaline, both in adipocyte cell cultures and in intact experimental animals.11,13 In the present study, we further investigated the nature of the human leptin-sympathetic nervous link by measuring arterial plasma leptin concentrations in clinical models of increased (cardiac failure, essential hypertension, nitroprusside infusion) or reduced (PAF, clonidine dosing) sympathetic tone, in which modified catecholaminergic inhibition of leptin release might be expected. We also tested for a linkage between regional sympathetic activity and plasma leptin concentration across a broad range of leptin values present in men of widely differing adiposity.. Our main objective was to determine whether sympathetic tone dictates leptin release. Results from previous studies suggest that the sympathetic nervous system exerts an inhibitory control over leptin production and ...
TY - JOUR. T1 - Serum leptin concentration, body composition, and gonadal hormones during puberty. AU - Demerath, E. W.. AU - Towne, B.. AU - Wisemandle, W.. AU - Blangero, J.. AU - Chumlea, W. Cameron. AU - Siervogel, R. M.. PY - 1999/1/1. Y1 - 1999/1/1. N2 - BACKGROUND: Recent evidence has suggested that leptin concentration is associated with gonadal hormone levels, and that changes in leptin concentration may trigger the onset of reproductive function in children. However, the concurrent changes in body composition during puberty make the independent associations between leptin and gonadal hormone concentrations in children difficult to resolve. METHODS: To investigate the nature of associations between leptin levels and pubertal maturation, serum concentrations of leptin, estradiol, and testosterone and body composition measures were examined in a sample of 152 healthy pre-pubertal, pubertal, and post-pubertal children. RESULTS: Leptin concentration was nearly three-fold higher in ...
Over the course of the past Fifteen years, we have observed that recombinant leptin has improved metabolic abnormalities in subjects with lipoatrophy and leptin deficiency . The mechanism by which leptin treatment improves insulin sensitivity in lipodystrophy patients is correlated with the decrease in triglyceride content that occurs in the liver and muscle tissues during leptin therapy, but it is unclear if this completely accounts for the increase in insulin sensitivity .. We followed two patients with mutations to their insulin receptor, who were refractory to standard insulin resistance treatment. We administered recombinant leptin hormone for 10 months to these two patients and observed the effect on insulin sensitivity and glucose tolerance in a pilot protocol.. Initial results from this study demonstrated that the two patients with extreme insulin resistance responded to leptin therapy by decreasing HgbA1c, decreasing fasting serum glucose levels, decreasing fasting serum insulin levels, ...
TY - JOUR. T1 - Seasonal and dose-dependent effects of intracerebroventricular leptin on lh secretion and appetite in sheep. AU - Miller, D W. AU - Findlay, P A. AU - Morrison, M A. AU - Raver, N. AU - Adam, C L. PY - 2002. Y1 - 2002. N2 - The role of leptin in neuroendocrine appetite and reproductive regulation remains to be fully resolved. A series of three experiments was conducted using adequately nourished oestradiol-implanted castrated male sheep. In a cross-over design (n=6), responses to a single i.c.v. (third ventricle) injection of leptin (0.5, 1.0 and 1.5 mg ovine leptin (oLEP) and 1.0 mg murine leptin (mLEP)), N-methyl-D-aspartate (NMDA, 20 micro g) or 0.9% saline (control) were measured in terms of LH secretion (4 h post-injection compared with 4 h pre-injection) and appetite (during 2 h post-injection) in autumn (Experiment 1). NMDA and 1.0 mg oLEP treatments were repeated in the same sheep in the following spring (Experiment 2). With an additional 12 sheep (n=18 in cross-over ...
Leptin was identified as a protein product of the obese gene. Mice with mutations in the obese gene that block the synthesis of leptin have been found to be obese and diabetic and to have reduced activity, metabolism and body temperature. Leptin expression is restricted to adipose tissue. Leptin binds to a high affinity receptor (OB-R) with homology to gp130 and G-CSF-R. OB-R is expressed in the choroid plexus, in the hypothalamus and in very primitive hematopoietic cell populations. Mouse leptin cDNA encodes a 167 amino acid protein containing a 21 amino acid signal peptide. The recombinant methionyl form of mouse leptin contains 147 amino acid residues and has a predicted molecular mass of approximately 16 kDa ...
Leptin levels are regulated by nutritional status and fall rapidly during starvation. Leptin deficiency is associated with impaired cell-mediated immunity, an increased incidence of infectious disease, and an associated increase in mortality (6, 10, 11). To date, studies into the influence of leptin on immunity have primarily focused on the adaptive immune response, especially that elicited by CD4+ T cells (6, 7, 12, 25). The administration of recombinant human leptin increases circulating T cell numbers and reverses the T cell hyporesponsiveness (proliferation and cytokine release) that is observed in children congenitally deficient in leptin (5). However, despite its clear influence on adaptive immunity, little is currently known about the effects of leptin on the innate immune system, particularly neutrophil function.. Previous studies have reported the presence of a leptin receptor on peripheral blood PMN (26), and we have confirmed this on isolated PMN. The proportion of PMN expressing the ...
The failure of obesity treatments to sustain weight reduction is widely recognized. The central hypotheses of these studies are that: 1.) Energy and neuroendocrine homeostastic systems are altered during the maintenance of a reduced body weight in a manner that favors weight regain; 2.) These changes occur because weight-reduced individuals are in a state of relative leptin deficiency due to loss of body fat; and 3.) Therefore these changes accompanying the maintenance of a reduced body weight will be reversed if circulating leptin concentrations are restored to those that were present prior to weight reduction.. Maintenance of a reduced body weight is associated with integrated autonomic and neuroendocrine changes that reduce energy expenditure and increase food intake in a manner that is similar to that seen in rodents and humans who are deficient in, or resistant to, the adipocyte-derived hormone leptin. Systemic leptin administration to leptin-deficient rodents and humans reverses the ...
Various malignancies are reproducibly cured in mouse models, but most cancer immunotherapies show objective responses in a fraction of treated patients. One reason for this disconnect may be the use of young, lean mice lacking immune-altering comorbidities present in cancer patients. Although many cancer patients are overweight or obese, the effect of obesity on antitumor immunity is understudied in preclinical tumor models. We examined the effect of obesity on two immunotherapeutic models: systemic anti-CTLA-4 mAb and intratumoral delivery of a TRAIL-encoding adenovirus plus CpG. Both therapies were effective in lean mice, but neither provided a survival benefit to diet-induced obese BALB/c mice. Interestingly, tumor-bearing leptin-deficient (ob/ob) obese BALB/c mice did respond to treatment. Moreover, reducing systemic leptin with soluble leptin receptor:Fc restored the antitumor response in diet-induced obese mice. These data demonstrate the potential of targeting leptin to improve tumor ...
The food source is used to increase leptin levels. Although, Leptin is a hormone that is responsible for many actions to increase leptin levels. Which also increase leptin levels are not so easy. Increase leptin levels can stimulate fat burning….. ...
TY - JOUR. T1 - Independent and additive effects of central POMC and leptin pathways on murine obesity. AU - Boston, Bruce A.. AU - Blaydon, Kathryn M.. AU - Varnerin, Jeffrey. AU - Cone, Roger D.. PY - 1997/11/28. Y1 - 1997/11/28. N2 - The lethal yellow (A(Y)/a) mouse has a defect in proopiomelanocortin (POMC) signaling in the brain that leads to obesity, and is resistant to the anorexigenic effects of the hormone leptin. It has been proposed that the weight-reducing effects of leptin are thus transmitted primarily by way of POMC neurons. However, the central effects of defective POMC signaling, and the absence of leptin, on weight gain in double-mutant lethal yellow (A(Y)/a) leptin-deficient (lep(ob)/lep(ob) mice were shown to be independent and additive. Furthermore, deletion of the leptin gene restored leptin sensitivity to A(Y)/a mice. This result implies that in the A(Y)/a mouse, obesity is independent of leptin action, and resistance to leptin results from desensitization of leptin ...
Personally I am not against a functional sort of leptin signalling inhibition being part of obesity, and certainly would be consistent with my history. My belief that leptin resistance is false, is the hypothesis that the leptin receptor is defective in obesity as Jack Kruse is apt to promote. My leptin receptors appear to be otherwise unremarkable, my leptin sensitivity appears to fluctuate with energy use (e.g. ketosis or not)... and certainly obesity does not manifest as a syndrome of total leptin resistance as true leptin insufficiency features specific phenotype that is inconsistent with regular obesity. Praeder willi patients are more like a leptin deficient/reistent model than a regular obese person, due to the fact they have persistent abnormalities indicating starvation like delayed growth and hypothyroidism and not entering puberty normally and a bias to build fat not lean tissue specifically, and very high ghrelin ...all suggesting leptin signalling is not happening at the brain level ...
TY - JOUR. T1 - The arcuate nucleus as a primary site of satiety effect of leptin in rats. AU - Satoh, Noriko. AU - Ogawa, Yoshihiro. AU - Katsuura, Goro. AU - Hayase, Minoru. AU - Tsuji, Tetsuo. AU - Imagawa, Keiichi. AU - Yoshimasa, Yasunao. AU - Nishi, Shigeo. AU - Hosoda, Kiminori. AU - Nakao, Kazuwa. PY - 1997/4/10. Y1 - 1997/4/10. N2 - The obese (ob) gene encodes a fat cell-derived circulating satiety factor (leptin) that is involved in the regulation of energy homeostasis. In the present study, we examined effects of i.c.v. injection of recombinant human leptin on food intake and body weight gain in rats. We also studied effects of direct microinjections of leptin into the arcuate nucleus (Arc), ventromedial hypothalamus (VMH), and lateral hypothalamus (LH). A single i.c.v. injection of recombinant human leptin (0.25-2.0 μg/rat) reduced significantly and dose-dependently food intake and body weight gain in rats. Microinjections (0.125-0.5 μg/site) into the bilateral Arc, VMH, and LH ...
is a hormone that plays a crucial role in appetite and weight control. It is thought to have at least two major functions. First, it crosses the blood-brain barrier and binds to receptors in the appetite center in the brain, regulating brain cells that tell you how much to eat.. Second, it increases sympathetic nervous system activity, which stimulates fatty tissue to burn energy. What is leptin resistance? Studies in mice have shown that giving animals leptin reduces overeating and obesity. However, many obese humans have been shown to have high amounts of leptin circulating in the blood, but it doesnt seem to affect appetite or energy expenditure. This is termed "leptin resistance," because even though the body has more than enough leptin in it, it doesnt respond to it the way its supposed to.. Why does leptin resistance happen? While the definitive cause of leptin resistance isnt known, there are two main hypotheses. The first is that leptin in the blood is for some reason not reaching ...
Benefits of cardiovascular exercise Practising the cardiovascular activity such as walking or jogging for about 30 minutes daily, can trigger the leptin hormone that was stored in a cell released into the bloodstream. Also, weight lifting can gain muscles which its also another means of releasing the leptin hormone into the body system.. Leptin hormone in a woman body Women naturally release more leptin hormone from their body compared to men. Leptin Resistance is often more prevalent in women. It, therefore, reduces the ability of the hormone to burn more fats to its ability. Also, women diet usually drop the level of leptin, which slow sow the level of metabolism. Womans body can as well go into the mode of starvation, which will make the body hold on to extra calories.. Venus-Factor-System treatment increases leptin sensitivity and also curb leptin resistance. A scientist or a doctor can develop perfect leptin diet. A Venus Factor was explicitly initiated to assist women. However, it always ...
Plasma leptin is higher in male patients who subsequently develop first-ever myocardial infarction than in control subjects.75 Leptin is also an independent predictor of myocardial infarction in men and especially women with arterial hypertension.76 Plasma leptin is higher in offspring with paternal history of premature myocardial infarction than in those without family history of cardiovascular events.77 Elevated plasma leptin predicts coronary events in men during a 5-year follow-up period.12 Plasma leptin is higher in patients who subsequently develop restenosis after coronary angioplasty than in those who do not.13 Leptin is an independent predictor of hemorhagic stroke in men and women14 and of stroke (ischemic and hemorrhagic stroke) in men but not in women.78 Furthermore, leptin is a predictor of myocardial infarction, coronary events, and stroke independent of body mass index (BMI).12,14,75,76,78 Significant correlations between leptin and intima-media thickness of the common carotid ...
Obesity is currently regarded as a pro-inflammatory condition during which leptin (Ob gene product) might act as a risk factor for Cardiovascular Diseases (CVD) including Acute Myocardial Infarction (AMI). There is a marked increase in circulating leptin concentrations and inflammatory markers such as Tumor Necrosis Factor-α (TNF-α) in AMI patients but still the association of leptin with inflammation during AMI is not known. The present study suggest that elevated levels of leptin might elicit the risk for CVD by signaling for the secretion of inflammatory cytokines especially, TNF-α. Blood samples were collected from 100 CVD subjects diagnosed for AMI immediately after their admission to the hospital and serum leptin, insulin, glucose, lipids and inflammatory marker such as TNF-α were measured. 5 ml random (non-fasting) blood was collected from 100 non-CVD (control) subjects and the results obtained in case of AMI subjects were compared with that of the control subjects. The subjects under study
Now, lets talk about leptin, another hormone….. Leptin is produced by the bodys fat cells. Basically what this hormone does is that it tells your brain that youre hungry when the leptin levels are low and you eat; when your leptin levels are high, it tells your brain that youre full and you stop eating. This is what happens in the ideal world: after we finish our meals, our leptin levels are high and we stop eating. After a few hours, our leptin levels drop to the point where the hormone "tells" our brains to eat to avoid hunger.. According to Dr. Ron Rosdale, an anti-aging expert, "Studies have shown that leptin plays significant if not primary roles in heart disease, obesity, diabetes, osteoporosis, autoimmune diseases, reproductive disorders, and perhaps the rate of aging itself. Many chronic diseases are now linked to excess inflammation such as heart disease and diabetes. High leptin levels are very pro-inflammatory, and leptin also helps to mediate the manufacture of other very ...
Introduction: Leptins role in bone formation has been reported, however, its mechanism of affecting bone metabolism is remaining unclear. In this study, we aimed to test whether leptin has a positive effect on fracture healing through the possible mechanism of increasing vascular endothelial growth factor (VEGF) expression in callus tissue. Methods: Standardized femur fractures were created in leptin-deficient ob/ob and wildtype C57BL/6J mice, and recombinant mouse leptin or its vehicle (physiological saline) was administered intraperitoneally during the study. Body weight, radiological, histologic and immunoblotting analyses were performed at different stages of fracture healing. Key findings: The results showed that leptin treatment led to lower rate of body weight change in both mice genotypes. Radiological and histological analyses showed that the experimental groups had better fracture healing at 14, 21 and 28 days compared to the control groups. Leptin-treated groups had signi?cantly ...
Defective central leptin signalling and impaired leptin entry into the CNS (central nervous system) represent two important aspects of leptin resistance in obesity. In the present study, we tested whether circulating human CRP (C-reactive protein) not only diminishes signalling of leptin within the CNS, but also impedes this adipokines access to the CNS. Peripheral infusion of human CRP together with co-infused human leptin was associated with significantly decreased leptin content in the CSF of ob/ob mice. Furthermore, following peripheral infusion of human leptin, the CSF (cerebrospinal fluid) concentration of leptin in transgenic mice overexpressing human CRP was sharply lower than that achieved in similarly infused wild-type mice. Administration of LPS (lipopolysaccharide) to human CRP-transgenic mice dramatically elevated the concentrations of human CRP in the CSF. The i.c.v. (intracerebroventricular) delivery of human CRP into the lateral ventricles of ob/ob mice blocked the satiety and ...
INTRODUCTION. Leptin, 16-kDa protein hormone, is produced by white adipose tissue. Structurally, it is a member of the IL-6 family of cytokines. Leptin is an anorexic peptide that is primarily known for its role as a hypothalamic modulator of food intake, body weight and fat stores1.. In addition to its effect on the hypothalamus, leptin is a modulator of the immune and proinflammatory responses. Leptin acts directly on T cells where it enhances the production of Th1 cells promoting inflammation2,3. Leptin also plays a significant role in, e.g., reproductive processes, angiogenesis, hematopoiesis and oxidation of lipids.. On the other hand, leptin had already been shown to be associated with asthma, and there have been reports that asthma and obesity are related4-7. The mechanisms by which leptin may be a risk factor for allergic rhinitis and asthma are not entirely understood, although a few recent studies have addressed this question4-9.. There is a close link between allergic rhinitis and ...
TY - GEN. T1 - Mathematically modeling the role of triglyceride production on leptin resistance. AU - Zhao, Yu. AU - Burkow, Daniel. AU - Song, Baojun. PY - 2019/1/1. Y1 - 2019/1/1. N2 - Diet-induced obesity is becoming more common all over the world, which is increasing the prevalence of obesity-induced chronic diseases such as diabetes, coronary heart disease, cancer, and sleep apnea. Many experimental results show that obesity is often associated with an elevated concentration of plasma leptin and triglycerides. Triglycerides inhibit the passage of leptin across the blood-brain barrier (BBB) to signal the hypothalamus to suppress appetite. However, it is still not clear how triglyceride concentration affects leptin transport across the BBB and energy balance. In this paper, we propose a novel ordinary differential equations model describing the role of leptin in the regulation of adipose tissue mass. Analytical and numerical results are analyzed using biologically relevant parameter values. ...
PubMed journal article: Plasma leptin concentrations and OB gene expression in subcutaneous adipose tissue are not regulated acutely by physiological hyperinsulinaemia in lean and obese humans. Download Prime PubMed App to iPhone, iPad, or Android
The results of this study showed significant increases of leptin mRNA expression in blood samples of dogs with CHF, differences in expression depending on CDs, and severity of disease, region of the heart, and possibly sex of the dog. There was no significant association with BCS, but a trend suggesting higher leptin concentrations with increased weight was present.. Increased concentrations of leptin in blood samples of dogs with decompensated CHF and myocardial samples of dogs with acquired CD and refractory heart failure were not surprising. Increased leptin concentrations were reported in human patients with heart failure and in animal models.[17, 19, 27] Because only single dogs in the present study showed evidence of cardiac cachexia, a reduction of leptin concentrations, which occurs in cardiac cachexia,[9, 29, 30] was not detected.. An increase of leptin blood concentrations is reported to correlate with heart failure class, exercise intolerance and is of prognostic value in people.[17, ...
Leptin reduces adiposity and exerts antisteatotic effects on nonadipose tissues. However, the mechanisms underlying leptin effects on lipid metabolism in liver and white adipose tissue have not been fully clarified. Here, we have studied the effects of central leptin administration on key enzymes an …
TY - JOUR. T1 - Overnight hypoxic exposure and glucagon-like peptide-1 and leptin levels in humans. AU - Snyder, Eric M.. AU - Carr, Richard D.. AU - Deacon, Carolyn F.. AU - Johnson, Bruce David. PY - 2008/10. Y1 - 2008/10. N2 - Altitude exposure has been associated with loss of appetite and weight loss in healthy humans; however, the endocrine factors that contribute to these changes remain unclear. Leptin and glucagon-like peptide-1 (GLP-1) are peptide hormones that contribute to the regulation of appetite. Leptin increases with hypoxia; however, the influence of hypoxia on GLP-1 has not been studied in animals or humans to date. We sought to determine the influence of normobaric hypoxia on plasma leptin and GLP-1 levels in 25 healthy humans. Subjects ingested a control meal during normoxia and after 17 h of exposure to normobaric hypoxia (fraction of inspired oxygen of 12.5%, simulating approximately 4100 m). Plasma leptin was assessed before the meal, and GLP-1 was assessed premeal, at 20 ...
Cloning and Expression of the Duck Leptin Gene and the Effect of Leptin on Food Intake and Fatty Deposition in Mice - Duck;Leptin;Expression;Food Intake;Fatty Deposition;
The exact molecular mechanisms of increased adipogenesis and its relation to the development of atherosclerotic lesions still remain unclear. One focus of research has been leptin, which was discovered in 1994 and is considered one of the important peripheral signals affecting food intake and body weight balance.2 Leptin reduces appetite and can reduce obesity in leptin deficient (ob/ob) knock-out mice. However, the initial enthusiasm over the discovery of leptin and its potential as fat-fighter for the obese has been absorbed by the facts, which reveal that in obese humans leptin levels are increased and mutations of the leptin receptor gene are rare events. There is a strong correlation of plasma leptin concentrations in humans with total body fat mass and body mass index.3,4 Leptin production is about two-fold higher in females than in males and is affected by growth and energy consumption.2 The majority of obese humans with high levels of plasma leptin show a leptin insensitivity on the ...
Research Shows Leptin Link to OA A French study may have found a major culprit in the development of osteoarthritis (OA)?leptin. Leptin, an obesity-related hormone, is produced in the bodys fat tissue and regulates food intake and energy output. In a study of 20 patients with OA, the researchers tested for the presence of leptin in samples of synovial fluid and cartilage samples from the joints. Of the 20 participants, 11 were having knee replacement surgery and 9 were undergoing knee arthroscopy. The researchers compared the expression of leptin in the cartilage of the OA patients with that found in normal tissue. Also, they compared the concentration of leptin found in the synovial fluid of the OA patients with their body mass index (BMI), as well as the level of their OA severity.The results showed that leptin concentrations correlated with high BMI, and leptin expression in OA joints related to the grade of cartilage destruction. The researchers concluded that more research is needed on the ...
TY - JOUR. T1 - An osteoblast-dependent mechanism contributes to the leptin regulation of insulin secretion. AU - Hinoi, Eiichi. AU - Gao, Nan. AU - Jung, Dae Young. AU - Yadav, Vijay. AU - Yoshizawa, Tatsuya. AU - Kajimura, Daisuke. AU - Myers, Martin G.. AU - Chua, Streamson C.. AU - Wang, Qin. AU - Kim, Jason K.. AU - Kaestner, Klaus H.. AU - Karsenty, Gerard. PY - 2009/9. Y1 - 2009/9. N2 - Our work focuses on genetic and molecular mechanisms for the reciprocal regulation of bone and energy metabolism orchestrated by leptin and osteocalcin. In the context of this reciprocal regulation, the finding that leptin inhibits insulin secretion by β cells while osteocalcin favors it is surprising. In exploring the molecular bases of this paradox we found that leptin, as is the case for most of its functions, uses a neuronal relay to inhibit insulin secretion. Cell-specific gene-deletion experiments revealed that a component of this neuronal regulation is the sympathetic innervation to osteoblasts. ...
Obesity has emerged as one of the most burdensome conditions in modern society. In this context, understanding the mechanisms controlling food intake is critical. At present, the adipocyte-derived hormone leptin and the pancreatic β-cell derived hormone insulin are considered the principal anorexigenic hormones. Although leptin and insulin signal transduction pathways are distinct, their regulation of body weight maintenance is concerted. Resistance to the central actions of leptin or insulin is linked to the emergence of obesity and diabetes mellitus. A growing body of evidence suggests a convergence of leptin and insulin intracellular signaling at the insulin-receptor-substrate-phosphatidylinositol-3-kinase (IRS-PI3K) level. Moreover, numerous factors mediating the pathophysiology of leptin resistance, a hallmark of obesity, such as endoplasmic reticulum (ER) stress, protein tyrosine phosphatase 1B (PTP1B) and suppressor of cytokine signaling 3 (SOCS3) also contribute to insulin resistance. Recent
Generally speaking, studies show a neutral effect on average leptin levels during intermittent fasting. While the fasting period decreases circulating leptin, this is compensated by a big boost when refeeding. In comparison to conventional meal frequencies, intermittent fasting induces a "peak and valley"-pattern in leptin synthesis. Leptin secretion is thus entrained to the meal pattern and shifting meal timing causes a comparable shift in plasma leptin rhythm.. However, there are some interesting discrepancies here in that women actually show a big increase in mean leptin levels during intermittent fasting. This occurs even in the absence of weight gain which is all the more fascinating. In the quoted study, despite calorie intake being elevated in comparison to baseline intake, the women actually lost weight and lowered waist circumference and body fat percentage. Intermittent fasting was also shown to decrease neuropeptide-Y, a hormone that stimulates hunger. This could probably be explained ...
NEW YORK- New research provides an improved understanding of the role of leptin, a protein produced by the "obese" gene, in weight gain in humans, report investigators at Rockefeller University. Earlier this year a team led by Jeffrey Friedman, M.D., Ph.D., professor at The Rockefeller University gained much public attention with a study documenting a 30 percent weight loss in genetically obese mice given daily injections of leptin for two weeks. While receiving leptin, the mice ate less and increased their use of energy. In their latest study, the same investigators found that the greater the body mass and percent of fat, the higher the levels of leptin. In humans, the amount of leptin in blood highly correlated to a persons percent of body fat and his or her body mass index. However, the leptin level varied greatly from person to person. For example, the amount of leptin for some obese patients with BMIs larger than 40 was the same as for patients with BMIs less than 20. "We found the amount ...
Background: Leptin, a product of the ob gene involved in energy balance and the regulation of food intake, is secreted predominantly in adipose tissue and serum leptin levels are elevated in obese individuals. Epidemiological studies have revealed that obesity, especially visceral fat, raises the risk of colorectal cancer (CRC). However, data concerning the effect of leptin on CRC development are contradictory and difficult to interpret. The aim of this study was to investigate the impact of leptin deficiency on CRC development and to determine whether leptin acts as a tumor promoter.. Methods: We investigated chemical-induced colon tumors and aberrant crypt foci (ACF) formation using wild-type (WT) mice, leptin-deficient (ob/ob) mice and leptin receptor deficient (db/db) mice. Western blot analysis, PCR and immunohistochemistry were performed to examine the role of leptin signaling in the colonic epithelium.. Results: Ob/ob and db/db mice exhibited dramatically decreased tumor sizes, despite ...
Accumulating evidence suggests that leptin regulates energy homeostasis through direct actions on peripheral lipid and glucose metabolism.132 Fatty acid (FA) oxidation produces the major source of ATP to sustain contractile function of the heart. AMP-activated protein kinase (AMPK) has a key role as a fuel gauge in the heart and regulates cardiac FA oxidation by phosphorylation and inhibition of acetyl-coenzyme A (CoA) carboxylase, which then lowers malonyl-CoA levels and stimulates carnitine palmitoyltransferase-1-induced FA oxidation.133 AMPK activation is also known to reduce FA incorporation into triacylglycerol.134. Examination of leptin effects on cardiac FA oxidation confirmed that leptin infusion increases FA oxidation and triacylglycerol lipolysis in isolated working rat hearts, although this effect was independent of changes in the AMPK/acetyl-CoA carboxylase/malonyl/CoA axis. Neither did leptin affect glucose oxidation rates.135 Myocardial oxygen consumption was increased, possibly ...
Chan, K. [陳錦榮]. (1999). Studies on recombinant leptin and leptin-binding peptides. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_ ...
Leptin, is a hormone that synthesized by fat tissue, has an important role to regulate energy balance and metabolism and thus body weight. The influence of acute exercise and chronic exercise training on circulating leptin and its relationship with hormonal and metabolic changes that induce energy balance had been noted by researchers. The purpose of this study was comparison of serum leptin(L) , cortisol(C) and testosterone(T) responses to one bout acute aerobic exercise in active and non-active men. In this semi-empirical study, 18 men in two groups: nine active ( 21 /88 ±1/36yr with 6/11± 1/45yr active training for the preceding) and nine non- active (22/2±1/64yr with nonspecific training for the preceding) were not taking any medication, and were free of cardiac, respiratory, renal, or metabolic diseases, volunteered. Blood samples were collected before and immediately after 12 minutes intensive running exercise (cooper aerobic test).The concentrations of L, C and T serum was determined ...
Leptin research has exploded in the last five years, meaning that our understanding of the roles of this hormone are emerging as much more complex than originally proposed. At present, there seems to be many theories as to the function of leptin, most of which are related in some way to energy homeostasis. However, energy homeostasis is a complex system that as yet is not fully understood, therefore where exactly leptin fits in is still difficult to characterise. If one defines appetite as simply the desire for food, then no, leptin is not simply an appetite suppressant. This is too simplistic a description of leptins actions. While the control of appetite is one aspect that will lead to energy homeostasis, evidence obtained so far certainly indicates that the role of leptin is far more complex than being an appetite suppressant, and I shall attempt to describe here the main emerging theories of leptins actions ...
... ,Leptin is a proteohormone with a molecular weight of 16 kDa. Leptin is a protein encoded by the ob gene and produced by adipocytes [1,2]. Leptin is thought to play a key role in the regulation of body weight [1-3]. In the human, leptin levels are elevated with increasing adiposity in both men an,biological,biology supply,biology supplies,biology product
One thing I find interesting is that short term fasting -- that reduces endogenous triglyceride levels -- does not induce leptin resistance, while starvation (48 hr fast) elevated triglycerides and produced the impaired transport effect. In my crazy days I have fasted several days in a row and I can attest that hunger usually subsides somewhere after the 2nd day. This is in contrast with leptin action, so its not the leptin that is suppressing hunger in that scenario. This is interesting to me because some describe leptin as the controller of all things having to do with maintaining homeostasis, and yet something else has to be responsible for greater hunger early in a fast and substantially reduced hunger in "starvation". But if our ancestors got a bit pudgy, this makes sense in that theoretically their leptin levels should be elevated and so early in a fast leptin gets to the brain and suppresses hunger, but as the fast lengthens resistance builds so hunger builds. Like I said, this makes ...
Human leptin is a 16 kDa (146 amino acids) protein secreted from adipocytes and influences body weight homeostasis. In this report, active human leptin was successfully produced in the culture medium of Bacillus subtilis. After simple purification steps consisting of ammonium sulfate precipitation and anion-exchange column chromatography, 2.3 mg of leptin with a purity of greater than 95% was obtained from the 0.5 L culture with the recovery yield of 54.9%. The purified leptin showed the correct folding structure with one disulfide bond.
Another popular trend is the Leptin diet. Scientists have studied different types of foods that could help you control Leptin for weight loss. For example, a study showed that a low-fat, high-carbohydrate diet increased Leptin levels more than a high-fat, low-carbohydrate diet. However, there is no evidence that a specific diet can help you take the correct amount of Leptin or cure Leptin resistance. Some experts suggest that you can make small daily changes in food and habits to increase Leptin in your body ...
Background Leptin is thought to act as an important mediator in stress reactions. To date, no study has examined the association between psychological stress and leptin levels in children. This study aimed to assess the association between emotional symptoms and peer problems and serum leptin levels in children aged 10 years of the two population-based GINI-plus and LISA-plus birth cohorts.. Method Cross-sectional data from 2827 children aged 10 years were assessed with regard to leptin concentrations in serum and behavioral problems using the parent-reported Strengths and Difficulties Questionnaire (SDQ). Linear regression modeling was applied to determine the likelihood of elevated leptin levels in children with emotional symptoms and peer problems, controlling for socio-economic status (SES), body mass index (BMI), fasting serum leptin levels, pubertal development and sex hormones.. Results We found that increases in emotional symptoms (exp β adj = 1.03, s.e. = 0.02, p , 0.04) and peer ...