Differential effect of transdermal estrogen plus progestagen replacement therapy on insulin metabolism in postmenopausal women: relation to their insulinemic secretion.
(1/23)
OBJECTIVE: To evaluate the impact on glucose and insulin metabolism of transdermal estrogen patches before and after the addition of cyclic dydrogesterone in postmenopausal women. DESIGN: We studied 21 postmenopausal women seeking treatment for symptomatic menopause. All patients received transdermal 50 micrograms/day estradiol for 24 weeks. After 12 weeks of treatment, 10 mg/day dydrogesterone were added. METHODS: During both regimens, insulin and C-peptide plasma concentrations were evaluated after an oral glucose tolerance test (OGTT); insulin sensitivity was evaluated by a hyperinsulinemic euglycemic clamp technique. Insulin and C-peptide response to OGTT were expressed as area under the curve (AUC) and as incremental AUC; insulin sensitivity was expressed as mg/kg body weight. Fractional hepatic insulin extraction (FHIE) was estimated by the difference between the incremental AUC of the C-peptide and insulin divided by the incremental AUC of the C-peptide. Plasma hormone and lipid concentrations were assessed at baseline and at 12 and 24 weeks of treatment. RESULTS: Nine patients proved to be hyperinsulinemic and 12 were normoinsulinemic. Transdermal estrogen treatment significantly decreased the insulin AUC (P < 0.05) and the insulin incremental AUC in hyperinsulinemic patients; addition of dydrogesterone further decreased both the AUC and incremental AUC of insulin. Estrogen alone and combined with dydrogesterone evoked a significant increase in C-peptide AUC in hyperinsulinemic (79.2%) and normoinsulinemic (113%) patients. The treatment increased the values for FHIE and insulin sensitivity in all patients (P < 0.04) and in the hyperinsulinemic group (P < 0.01), whereas it did not affect such parameters in normoinsulinemic patients. CONCLUSIONS: Transdermal estrogen substitution alone and combined with cyclical dydrogesterone may ameliorate hyperinsulinemia in a selected population of postmenopausal women. (+info)
The effect of different hormone therapies on integrin expression and pinopode formation in the human endometrium: a controlled study.
(2/23)
BACKGROUND: Integrin expression and pinopode formation have been proposed as a means of distinguishing receptive endometrium from non-receptive in clinical practice, thus offering new directions for the development of contraceptive approaches targeted to the endometrium as well as a better understanding of occult causes of infertility in women. The aim of the present study was to investigate the effect of ovulation induction, oral contraception, treatment with dehydrogesterone, and different regimens of hormone replacement therapy on endometrial alphavbeta3 integrin expression and pinopode formation using a prospective, controlled study design. METHODS: Histological dating, alphavbeta3 integrin expression and pinopode formation were evaluated in control and treated cycles in six groups of women including eight subjects per group and who received clomiphene citrate, ovarian stimulation for IVF, oral contraception, dehydrogesterone for endometrial luteal phase defect, or two different regimens of hormone replacement therapy. Twelve healthy fertile women served as a general control group. RESULTS: Alphavbeta3 integrin expression and pinopode formation in the human endometrium were closely related to endometrial maturation as defined by histological dating and this was irrespective of endometria being in-phase or out-of-phase and the hormonal treatment received. Only for clomiphene citrate did a direct effect with reduction in pinopode formation in the midluteal phase seem to exist. CONCLUSION: Alphavbeta3 integrin expression and pinopode formation in the human endometrium are processes closely related to endometrial maturation and this is irrespective of endometria being in-phase or out-of-phase and the hormonal treatment received. The potential usefulness of those two so-called endometrial markers of implantation as targets for contraceptive approaches or fertility-promoting strategies seems unlikely. (+info)
The effect of synthetic gestagens on progesterone formation in vitro in human placenta of early pregnancy.
(3/23)
Villous tissue from 26 placentae of 7-17 weeks was incubated with radioactive pregnenolone alone and with pregnenolone in the presence of progesterone and 9 synthetic gestagenic steroids and the progesterone formation was measured after 30 min. When progesterone was present in a concentration of 31 or 310 mumol/1 the conversion rate of labelled pregnenolone to progesterone was reduced to 88.6 and 82.2% of that of the respective control incubations. Dydrogesterone, allyloestrenol, lynoestrenol and norethynodrel under similar conditions did not inhibit the formation of progesterone. The inhibitory effects of megoestrol acetate, medroxyprogesterone acetate and norgestrel were close to that of progesterone. Norethisterone and methyloestrenolone were the most effective inhibitors of progesterone formation: when incubated in an equimolar concentration (35 mumol/1) with pregnenolone (50 microgram) the progesterone formation was reduced to 60.0-62.7% and 29.1-34.0% respectively of that of the respective control experiments. (+info)
Depletion of CD8+ cells abolishes the pregnancy protective effect of progesterone substitution with dydrogesterone in mice by altering the Th1/Th2 cytokine profile.
(4/23)
One of the most remarkable immunological regulations is the maternal immune tolerance toward the fetal semiallograft during pregnancy, which has been referred to as immunity's pregnant pause. Rejection of the semiallogeneic trophoblast cells must be selectively inhibited and pathways presumably include Th2 cytokines unopposed by Th1 cytokines. Steroid hormones, including progesterone, have similar effects. Low levels of progesterone and Th2 cytokines and high levels of Th1 cytokines are attributable for increased abortions in mammalians, which may be triggered by psychoemotional stress. Thus, the aim of the present study was to provide experimental evidence for the mechanism involved in the mediation of immune responses by endocrine signals during pregnancy and stress-triggered pregnancy failure. DBA/2J-mated CBA/J female mice were randomized in three groups: 1) control females, 2) mice exposed to stress on gestation day 5.5, and 3) mice exposed to stress and substituted with dydrogesterone, a progestogen with a binding profile highly selective for the progesterone receptor on gestation day 5.5. On gestation days 7.5, 9.5, and 10.5, mice of each group were sacrificed, and the frequency of CD8(+) cells and cytokine expression (IL-4, IL-12, TNF-alpha, IFN-gamma) in blood and uterus cells was evaluated by flow cytometry. Additionally, some mice were depleted of CD8 cells by injection of mAb. We observed that progesterone substitution abrogated the abortogenic effects of stress exposure by decreasing the frequency of abortogenic cytokines. This pathway was exceedingly CD8-dependent, because depletion of CD8 led to a termination of the pregnancy protective effect of progesterone substitution. (+info)
Effects of tibolone and cyclic hormone replacement therapy on glucose metabolism in non-diabetic obese postmenopausal women: a randomized study.
(5/23)
OBJECTIVE AND METHODS: To study the effects of hormone replacement therapy on glucose metabolism, 31 obese (body mass index > or =27 kg/m(2)) postmenopausal women were randomized to treatment with tibolone (2.5 mg once daily; TIB; n=16) or to oestradiol valerate (2 mg daily)-dydrogesterone (20 mg daily for 2 weeks every 3 months; ED; n=15) for 12 months. Oral (OGTTs) and intravenous glucose tolerance tests (IVGTTs) and a euglycaemic hyperinsulinaemic clamp were performed before and at 6 and 12 months of treatment. RESULTS: TIB decreased the rates of whole body glucose uptake (WBGU) at 6 (P=0.04) and 12 months (P<0.001), but it did not have a significant effect on glucose tolerance. In OGTTs, serum insulin and C-peptide concentrations 2 h after the oral glucose load were increased (P<0.001 and P=0.05 respectively) at 12 months of treatment with TIB, but no changes in the areas under the curve (AUC) of insulin or C-peptide were observed. Furthermore, TIB did not have a significant effect on insulin secretion, the metabolic clearance rate (MCR) of insulin or hepatic insulin extraction. Treatment with ED did not modify the rates of WBGU, but it increased the MCR of insulin (P=0.017) and hepatic insulin extraction (P<0.001) and tended to decrease the insulin AUC (P=0.07). Moreover, glucose tolerance slightly deteriorated during this treatment (P=0.02). Although early phase insulin secretion evaluated by the serum C-peptide response at 30 min in the OGTT increased (P=0.046), the first-phase insulin response during the IVGTT decreased (P=0.05) during ED treatment. CONCLUSIONS: Despite the impairment in peripheral insulin sensitivity, TIB treatment had a neutral effect on glucose tolerance, possibly due to a compensatory decrease in endogenous glucose production. The increased demand on insulin induced by ED, due to both a stimulatory effect on pancreatic beta cells and increased insulin metabolism, may explain the slightly detrimental effect on glucose tolerance with this treatment. (+info)
Dydrogesterone (Duphaston) and its 20-dihydro-derivative as selective estrogen enzyme modulators in human breast cancer cell lines. Effect on sulfatase and on 17beta-hydroxysteroid dehydrogenase (17beta-HSD) activity.
(6/23)
Estradiol (E2) is one of the main factors which control the growth and evolution of breast cancer. Consequently, to block the formation of E2 inside cancer cells has been an important target in recent years. Breast cancer cells possess all the enzymatic systems (e.g. sulfatase, aromatase, 17beta-hydroxysteroid dehydrogenase [17beta-HSD]) involved in the conversion of estrogen precursors into E2. Sulfotransferase, which converts estrogen to its sulfate, is also present in this tumoral tissue. Duphaston is a synthetic progestogen with properties similar to the natural progesterone. In the present study we examined the effect of Duphaston and its 20-dihydro-metabolite on the sulfatase and 17beta-HSD activities in MCF-7 and T-47D breast cancer cells. The cells were incubated with estrone sulfate (E1S) (5x10(-9)M) in the absence or presence of Duphaston or its 20-dihydro-metabolite (5x10(-5) to 5x10(-9)M) for 24h at 37 degrees C. In another series of experiments, estrone (E1) (5x10(-9)M) was incubated with T-47D cells in the absence or presence of the two progestogens (5x10(-5) to 5x10(-9)M) for 24h at 37 degrees C. E1S, E1 and E2 were characterized by thin layer chromatography and quantified using the corresponding standard. Duphaston and its 20-dihydro-metabolite, at concentrations of 5x10(-7) and 5x10(-5)M, inhibited the conversion of E1S to E2 by 14% and 63%, 65% and 74%, respectively, in MCF-7 cells; the values were 15% and 48% and 31% and 51%, respectively, in T-47D cells. In another series of experiments it was observed that, after 24-h incubation, E1 (5x10(-9)M) was converted in a great proportion to E2 in the T-47D cells and that this transformation was significantly inhibited by Duphaston and its 20-dihydro-metabolite. The IC50 value, corresponding to 50% of the inhibition in the conversion of 1 to E2, was 9x10(-6)M for 20-dihydro-metabolite in this cell line. It was concluded that the progestogen Duphaston and its 20-dihydro-metabolite are potent inhibitory agents on sulfatase and 17beta-HSD activities in breast cancer cells. Duphaston is a progestogen with properties similar to the endogenous progesterone. The data open interesting perspectives to study the biological responses of these progestogens in clinical trials of patients with breast cancer. (+info)
The effect of HRT on cerebral haemodynamics and cerebral vasomotor reactivity in post-menopausal women.
(7/23)
BACKGROUND: Cerebral vasomotor reactivity (CVR) is an index of cerebrovascular dilatory capacity which can readily be assessed using trans-cranial Doppler ultrasound. Impaired CVR is associated with elevated risk of stroke. We performed a randomized, double-blind placebo-controlled trial to investigate the effect of two HRT preparations upon CVR. METHODS: We examined middle cerebral artery mean flow velocity (MFV), internal carotid artery pulsatility index (PI) and CVR to an i.v. acetazolamide bolus using ultrasound in three groups of post-menopausal women randomized to oral estradiol 1 mg+norethisterone 0.5 mg (group N), estradiol 1 mg+dydrogesterone 5 mg (group D) or placebo (group P). The MFV, PI and CVR were measured before and after 3 months treatment. RESULTS: Thirty-eight post-menopausal women were recruited (N=12, D=14, P=12); mean (SE) age was 56.7 (4) years. Neither HRT preparation affected CVR [% (SE) change from baseline N +4.2 (11); D +3.8 (5.5); P +4.0 (3.8); all comparisons P = NS]. PI was significantly reduced in recipients of dydrogesterone [% (SE) change from baseline D -5.4% (4.6); N +12.3 (6.9); P +11.6 (6.9). P=0.025]. Middle cerebral artery velocity was significantly increased following dydrogesterone treatment compared with placebo [% (SE) change from baseline D +6.8 (3.4) N +3.9 (4.2) P -4.6% (3.4) P=0.03 for D versus P]. CONCLUSION: HRT did not alter CVR. The reduced PI and increased MFV suggest HRT-induced intracranial vasodilatation, which is more apparent in dydrogesterone recipients. Differences may exist between progestogens with regard to changes in intracranial haemodynamics. (+info)
Endometrial preparation for in vitro oocyte maturation: early use of estrogen increases endometrial tissue and requires lower daily dosage: a cross over trial in 'mock' cycles.
(8/23)
PURPOSE: Determine if estrogen used since the beginning of the menstrual flow could improve endometrial tissue compared to standard endometrial preparation for in vitro maturation cycles. METHODS: Twenty polycystic ovary syndrome women were submitted to two estrogen therapy schedules: standard schedule; estrogen began on the day of planned egg retrieval (dosage was based on endometrial thickness); and long schedule; estrogen began on the first day of menstruation. No oocyte retrieval or embryo transfer was performed. Three-dimensional ultrasound was performed on the day of planned egg retrieval and one week later for endometrial evaluation. RESULTS: A higher endometrial thickness and volume was found in long schedule on both evaluations. The number of patients that have used 10 mg/day of estradiol was significant higher in the standard schedule (65%x0%). No other significant difference was found. CONCLUSIONS: The early use of estrogen improves endometrial tissue and requires lower daily dosage. (+info)