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, fibromyalgia, late-onset congenital adrenal hyperplasia, diabetes mellitus and rheumatoid arthritis. 2) The regulation of the axis by opioids, vasopressin, oxytocin, glucocorticoids, eicosanoids, platelet activating factor (PAF), tumor necrosis factor - alpha, interleukin-6, 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 and in vivo. Third trimester pregnant women and athletes have a hyperfunctional pituitary-adrenal axis in the resting 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. It has 2 active promoters and responds positively to estrogens, providing a potential explantation for the sexual dimorphism of psychiatric diseases characterized by abberations in CRH secretion. 3) Role and actions of glucocorticoids: Surgical stress is associated with continuous and pulsatile secretion of ACTH. Glucocorticoid resistance is an autosomal recessive or dominant disease associated with abnormalities of the glucocorticoid receptor type II. We have elucidated the molecular pathophysiology of this syndrome by defining mutations and/or deletion of the glucocorticoid receptor gene leading to abnormal or decreased receptors in the tissues of patients. The glucocorticoid receptor type I (mineralocorticoid) is studied in several kindreds with mineralocorticoid resistance. The interaction of the glucocorticoid receptor with the heat-shock proteins is studied. Hereditary ACTH resistance is an autosomal recessive disorder characterized by pituitary glucocorticoid deficiency. We have elucidated the molecular pathophysiology of this syndrome by defining abnormalities of the ACTH receptor gene.
Showing the most recent 10 out of 191 publications
