In vivo evidence that endogenous dopamine modulates sympathetic activity in man.
Dopamine receptors type 2 (D2)-like receptor blockers cause an increase in the norepinephrine response to intense physical exercise. However, during intense physical exercise, D2-like antagonists also cause an increase in the epinephrine response, which itself might cause an increase in plasma norepinephrine through the activation of beta2 presynaptic receptors. Therefore, we evaluated the effect of domperidone, a D2-like antagonist, on the norepinephrine response to physical exercise in 6 Addison patients (3 were adrenalectomized and 3 had adrenal tuberculosis). In these patients, the norepinephrine increase observed during exercise was significantly higher after the administration of domperidone than a placebo (F=4,328; P<0.001). Because peripheral plasma norepinephrine does not reflect the sympathetic tone to the heart accurately, we evaluated the effect of domperidone administration (20 mg orally) on the sympathovagal balance, which was measured by the ratio between the high- and low-frequency components of heart rate variability, in 9 normal volunteers in the supine and sitting positions. When compared with placebo, domperidone caused a significant increase in the low/high frequency ratio (P<0.05) in the sitting position without modifying basal and stimulated norepinephrine plasma levels or blood pressure. These data support a role for endogenous dopamine in modulating norepinephrine release by human sympathetic nerves in vivo. (+info)
Traumatic adrenal injury in children.
BACKGROUND: Multiple organ injury in children is an increasingly frequent phenomenon in the modern emergency room. Adrenal hemorrhage associated with this type of trauma has received little attention in the past. OBJECTIVES: Using computed tomography, we sought to determine the rate and nature of adrenal gland injury in children following blunt abdominal trauma due to motor vehicular accident. METHODS: A total of 121 children with blunt abdominal trauma were examined and total body CT was performed in cases of multi-organ trauma or severe neurological injury. RESULTS: Of all the children who presented with blunt abdominal trauma over a 51 month period, 6 (4.95%) had adrenal hemorrhage. In all cases only the right adrenal gland was affected. Coincidental injury to the chest and other abdominal organs was noted in 66.7% and 50% of patients, respectively. CONCLUSIONS: Traumatic adrenal injury in the pediatric population may be more common than previously suspected. Widespread application of the more sophisticated imaging modalities available today will improve the detection of damage to the smaller organs in major collision injuries and will help in directing attention to the mechanism of trauma. (+info)
A case of hypothalamic adrenal insufficiency manifested normal ACTH response to insulin-induced hypoglycemia.
A low plasma ACTH response to insulin-induced hypoglycemia and an exaggerated and delayed plasma ACTH response to CRH stimulation have been considered as an indicator of hypothalamic hypopituitarism. We report a case of hypothalamic adrenal insufficiency which manifested normal ACTH response to insulin-induced hypoglycemia. This case provides important information to categorize hypothalamic adrenal insufficiency caused by abnormal regulation of CRH release. (+info)
Apparently normal ovarian differentiation in a prepubertal girl with transcriptionally inactive steroidogenic factor 1 (NR5A1/SF-1) and adrenocortical insufficiency.
Steroidogenic factor 1 (NR5A1/SF-1) plays an essential role in the development of the hypothalamic-pituitary-adrenal and hypothalamic-pituitary-gonadal axes, controlling expression of their many important genes. The recent description of a 46,XY patient bearing a mutation in the NR5A1 gene, causing male pseudohermaphroditism and adrenal failure, demonstrated the crucial role of SF-1 in male gonadal differentiation. The role of SF-1 in human ovarian development was, until now, unknown. We describe a phenotypically and genotypically normal girl, with signs and symptoms of adrenal insufficiency and no apparent defect in ovarian maturation, bearing a heterozygote G-->T transversion in exon 4 of the NR5A1 gene that leads to the missense R255L in the SF-1 protein. The exchange does not interfere with protein translation and stability. Consistent with the clinical picture, R255L is transcriptionally inactive and has no dominant-negative activity. The inability of the mutant (MUT) NR5A1/SF-1 to bind canonical DNA sequences might offer a possible explanation for the failure of the mutant protein to transactivate target genes. This is the first report of a mutation in the NR5A1 gene in a genotypically female patient, and it suggests that NR5A1/SF-1 is not necessary for female gonadal development, confirming the crucial role of NR5A1/SF-1 in adrenal gland formation in both sexes. (+info)
Endoscopic retroperitoneal adrenalectomy: lessons learned from 111 consecutive cases.
OBJECTIVE: To evaluate the effectiveness of endoscopic retroperitoneal adrenalectomy (ERA). SUMMARY BACKGROUND DATA: Minimally invasive adrenalectomy has become the procedure of choice for benign adrenal pathology. Although the adrenal glands are located in the retroperitoneum, most surgeons prefer the transperitoneal laparoscopic approach to adrenal tumors. METHODS: Clinical characteristics and outcomes of 111 ERAs from January 1994 to December 1999 were evaluated. RESULTS: Ninety-five patients underwent 111 ERAs (79 unilateral, 16 bilateral). Indications were Cushing syndrome (n = 22), Cushing disease (n = 8), ectopic adrenocorticotropic hormone syndrome (n = 6), Conn's adenoma (n = 25), pheochromocytoma (n = 19), incidentaloma (n = 11), and other (n = 4). Tumor size varied from 0.1 to 8 cm. Median age was 50 years. Unilateral ERA required 114 minutes, with median blood loss of 65 mL. Bilateral ERA lasted 214 minutes, with median blood loss of 121 mL. The conversion rate to open surgery was 4.5%. The complication rate was 11%. Median postoperative hospital stay was 2 days for unilateral ERA and 5 days for bilateral ERA. The death rate was 0.9%. At a median follow-up of 14 months, the recurrence rate of disease was 0.9%. CONCLUSION: For benign adrenal tumors less than 6 cm, ERA is recommended. (+info)
Evaluation of incidental renal and adrenal masses.
Incidental renal or adrenal masses are sometimes found during imaging for problems unrelated to the kidneys and adrenal glands. Knowledgeable family physicians can reliably diagnose these masses, thereby avoiding unnecessary worry and procedures for their patients. A practical and cost-efficient means of evaluating renal lesions combines ultrasonography and computed tomographic scanning, with close communication between the family physician and the radiologist. Asymptomatic patients with simple renal cysts require no further evaluation. Patients with minimally complicated renal cysts can be followed radiographically. Magnetic resonance imaging is indicated in patients with indeterminate renal masses, and referral is required in patients with symptoms or solid masses. The need for referral of patients with adrenal masses is determined by careful assessment of clinical signs and symptoms, as well as the results of screening laboratory studies and appropriate radiologic studies. Referral is indicated for patients with incidental adrenal masses more than 6 cm in greatest diameter. Appropriate laboratory screening tests include the following: a 24-hour urinary free cortisol measurement for patients with evidence of Cushing's syndrome; a 24-hour urinary metanephrine, vanillylmandelic acid or catecholamine measurement for patients with evidence of pheochromocytoma; and a serum potassium level for patients with evidence of hyperaldosteronism. (+info)
Adrenal gland: structure, function, and mechanisms of toxicity.
The adrenal gland is one of the most common endocrine organs affected by chemically induced lesions. In the adrenal cortex, lesions are more frequent in the zona fasciculata and reticularis than in the zona glomerulosa. The adrenal cortex produces steroid hormones with a 17-carbon nucleus following a series of hydroxylation reactions that occur in the mitochondria and endoplasmic reticulum. Toxic agents for the adrenal cortex include short-chain aliphatic compounds, lipidosis inducers, amphiphilic compounds, natural and synthetic steroids, and chemicals that affect hydroxylation. Morphologic evaluation of cortical lesions provides insight into the sites of inhibition of steroidogenesis. The adrenal cortex response to injury is varied. Degeneration (vacuolar and granular), necrosis, and hemorrhage are common findings of acute injury. In contrast, chronic reparative processes are typically atrophy, fibrosis, and nodular hyperplasia. Chemically induced proliferative lesions are uncommon in the adrenal cortex. The adrenal medulla contains chromaffin cells (that produce epinephrine, norepinephrine, chromogranin, and neuropeptides) and ganglion cells. Proliferative lesions of the medulla are common in the rat and include diffuse or nodular hyperplasia and benign and malignant pheochromocytoma. Mechanisms of chromaffin cell proliferation in rats include excess growth hormone or prolactin, stimulation of cholinergic nerves, and diet-induced hypercalcemia. There often are species specificity and age dependence in the development of chemically induced adrenal lesions that should be considered when interpreting toxicity data. (+info)
New adrenal-scanning agent.
A new adrenal-specific compound, 6beta-iodomethyl-19-norcholest-5(10)-en-3beta-ol(NCL-3-I), which is derived from 19-iodocholesterol (CL-19-I), has been found. Tissue distribution studies have revealed that the rat adrenal gland accumulates ten times more NCL-6-131-I than CL-19-131-I. The advantage of NCL-6-131-I as a possible adrenal-scanning agent is discussed. (+info)