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HPA Function (hpa + function)
Selected AbstractsAlcohol self-administration acutely stimulates the hypothalamic-pituitary-adrenal axis, but alcohol dependence leads to a dampened neuroendocrine stateEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2008Heather N. Richardson Abstract Clinical studies link disruption of the neuroendocrine stress system with alcoholism, but remaining unknown is whether functional differences in the hypothalamic-pituitary-adrenal (HPA) axis precede alcohol abuse and dependence or result from chronic exposure to this drug. Using an operant self-administration animal model of alcohol dependence and serial blood sampling, we show that long-term exposure to alcohol causes significant impairment of HPA function in adult male Wistar rats. Acute alcohol (voluntary self-administration or experimenter-administered) stimulated the release of corticosterone and its upstream regulator, adrenocorticotropic hormone, but chronic exposure sufficient to produce dependence led to a dampened neuroendocrine state. HPA responses to alcohol were most robust in ,low-responding' non-dependent animals (averaging < 0.2 mg/kg/session), intermediate in non-dependent animals (averaging ,0.4 mg/kg/session), and most blunted in dependent animals (averaging ,1.0 mg/kg/session) following several weeks of daily 30-min self-administration sessions, suggesting that neuroendocrine tolerance can be initiated prior to dependence and relates to the amount of alcohol consumed. Decreased expression of corticotropin-releasing factor (CRF) mRNA expression in the paraventricular nucleus of the hypothalamus and reduced sensitivity of the pituitary to CRF may contribute to, but do not completely explain, neuroendocrine tolerance. The present results, combined with previous studies, suggest that multiple adaptations to stress regulatory systems may be brought about by excessive drinking, including a compromised hormonal response and a sensitized brain stress response that together contribute to dependence. [source] HPA-suppressive effects of aqueous clobetasol propionate in the treatment of patients with oral lichen planusJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 9 2010MA Gonzalez-Moles Abstract Background, Oral topical corticosteroids have potential to produce inhibition of the hypothalamus,pituitary,adrenal (HPA) axis. Objective, To assess whether clobetasol propionate (CP) in aqueous solution causes HPA inhibition. Patients and methods, Sixty-two patients with oral lichen planus or oral lichenoid lesions presenting with severe lesions were treated with topical oral 0.05% CP plus 100 000 IU/cm3 nystatin in aqueous solution. Initial treatment of three 5-min mouthwashes (10 mL) daily was reduced, when the response was deemed complete or excellent, to a maintenance treatment of one 5-min mouthwash on alternate days for 6 months; treatment was then withdrawn and patients were followed up for 1 year. HPA function was assessed by plasma cortisol measurement and adrenocorticotropin (ACTH) stimulation at the end of the initial and maintenance treatment regimens. Results, The HPA axis was more frequently inhibited during initial (53/62; 85.5%) vs. maintenance (2/49; 4%) regimens of aqueous CP. Limitations, In patients with morning plasma cortisol levels between 3 and 18 ,g/dL, a normal result for the ACTH stimulation test only moderately reduces the possibility that a patient has secondary adrenal insufficiency. This can be considered a minor limitation in our study, as only three patients required additional assessment with the ACTH stimulation test. Conclusions, Hypothalamus,pituitary,adrenal inhibition is substantial during initial treatment with aqueous CP three times daily. [source] Androgen receptor expressing neurons that project to the paraventricular nucleus of the hypothalamus in the male ratTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 6 2007Martin Williamson Abstract Androgen receptors are distributed throughout the central nervous system and are contained by a variety of nuclei that are known to project to or regulate the paraventricular nucleus (PVN) of the hypothalamus, the final common pathway by which the brain regulates the hypothalamic,pituitary,adrenal (HPA) response to homeostatic threat. Here we characterized androgen receptor staining within cells identified as projecting to the PVN in male rats bearing iontophoretic or crystalline injections of the retrograde tracer FluoroGold aimed at the caudal two-thirds of the nucleus, where corticotropin-releasing hormone-expressing neurons are amassed. Androgen receptor (AR) and FluoroGold (FG) double labeling was revealed throughout the limbic forebrain, including scattered numbers of cells within the anterior and posterior subdivisions of the bed nuclei of the stria terminalis; the medial zone of the hypothalamus, including large numbers of AR-FG-positive cells within the anteroventral periventricular and medial preoptic cell groups. Strong and consistent colabeling was also revealed throughout the hindbrain, predominantly within the periaqueductal gray and the lateral parabrachial nucleus, and within various medullary cell groups identified as catecholaminergic, predominantly C1 and A1 neurons of the ventral medulla. These connectional data predict that androgens can act on a large assortment of multimodal inputs to the PVN, including those involved with the processing of various types of sensory and limbic information, and provide an anatomical framework for understanding how gonadal status could contribute to individual differences in HPA function. J. Comp. Neurol. 503:717,740, 2007. © 2007 Wiley-Liss, Inc. [source] The low-dose (1 ,g) adrenocorticotropin stimulation test in kidney and kidney,pancreas transplant patients: a potential guideline for steroid withdrawalCLINICAL TRANSPLANTATION, Issue 1 2006M Baz-Hecht Abstract:, Chronic steroid treatment is known to impair the hypothalamic,pituitary adrenal axis (HPA) but the need to assess HPA function prior to withdrawal of steroid therapy in post-transplant patients has not been uniformly accepted. We evaluated the status of the HPA axis in 48 kidney or kidney,pancreas transplant patients who were considered for possible discontinuation of glucocorticoid therapy using a recently validated dynamic test of HPA integrity, the low-dose (1 ,g) adrenocorticotropin (ACTH) test. HPA suppression was detected in 29 (60%) of the patients, four of which had severe hypoadrenalism prohibitive of steroid withdrawal. Neither the duration of steroid treatment nor 8:00 am serum cortisol was a useful marker of hypoadrenalism. 8:00 am cortisol in subjects with normal HPA reserve and subjects with partial hypoadrenalism overlapped considerably but levels <5 ,g/dL were indicative of severe hypoadrenalism. Pre-withdrawal diagnosis of partial hypoadrenalism allowed the identification of subjects requiring no further steroid replacement under regular daily circumstances. However glucocorticoid supplementation was prescribed in the event of stress such as infection, exceptional effort, trauma or surgery. Individuals with partial HPA impairment, but not patients with severe HPA suppression, improved upon retesting 3 months later. Patients exhibiting normal response to 1 mcg ACTH enjoyed an uneventful course following steroid withdrawal. Since hypoadrenalism is extremely common in post-transplant patients, we recommend the use of the low-dose ACTH test as a convenient method to identify patients with various degrees of hypoadrenalism prior to steroid withdrawal. [source] | |||||||||||||