PHYSIOLOGY AND PATHOPHYSIOLOGY OF THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS

在这个项目中，我们试图推进对生理学和

In this project we seek to advance the understanding of the physiology and pathophysiology of the hypothalamic-pituitary-adrenal axis. The role of stress-related hormones in normal and disease states is being examined, and clinical applications for these hormones are sought. The recent discovery of the structure of corticotropin releasing hormone (CRH) and the development of sensitive assays for measuring stress-related hormones and their receptors have led to rapid progress in this field. Major progress has been made in three areas: 1) Clinical applications of CRH: An ovine CRH (oCRH) stimulation test has been developed that is useful in the differential diagnosis of adrenal insufficiency, Cushing's syndrome, and pseudo-Cushing's states (psychiatric hypercortisolism). The human CRH (hCRH) analog is useful in studying the physiology of the pituitary-adrenal axis. The oCRH stimulation test and measurement of CSF CRH have increased our understanding of the pathophysiology of Cushing's syndrome, melancholic depression, atypical depression, seasonal depression, the premenstrual tension syndrome, anorexia nervosa, the chronic fatigue syndrome and late- onset congenital adrenal hyperplasia. 2) The regulation of the axis by opioids, vasopressin, oxytocin, glucocorticoids, eicosanoids, platelet activating factor (PAF), tumor necrosis factor - alpha, cholecystokinin (CCK), neuropeptide Y, benzodiazepine agonists and antagonists and thyroid hormones has been studied in vivo and/or in vitro. Neurotransmitter and feedback regulation of hypothalamic CRH secretion has also been examined in vitro. Third trimester pregnant women and athletes have a hyperfunctional pituitary-adrenal axis in the testing state. Hypothalamic-pituitary- adrenal axis reactivity and personality traits have been correlated in developing adolescents. The hCRH gene 5' regulatory region has been cloned and sequenced and its regulation is being studied. 3) Role and actions of glucocorticoids: The effects of glucocorticoids upon the cardiovascular system during surgical stress are merely permissive. Surgical Stress is associated with continuous and pulsatile secretion of ACTH. Glucocorticoid resistance is an autosomal recessive or dominant disease associated with normal size glucocorticoid receptor protein that has decreased affinity for glucocorticoids and normal size mRNA. We have found a nonconservative point mutation (Asp -- > Val) in the steroid binding domain of the glucocorticoid receptor which leads to a decrease in the affinity of the receptor for glucocorticoids and decreased glucocorticoid effect. Several kindreds are being studied and different molecular mechanisms of glucocorticoid resistance are being found. The interaction of the glucocorticoid receptor with the heat-shock proteins is studied.