Vasoactive hormones and regulation of the hypothalamic-pituitary-adrenal axis

Survival under stress situations requires coordinated behavioral, autonomic and hormonal responses in order to maintain homeostasis. Activation of the autonomic system, the hypothalamic pituitary adrenal (HPA) axis with increase in plasma glucocorticoids is essential for this adaptation (1). The secretion of glucocorticoids is regulated by the pituitary peptide adrenocorticotropic hormone (ACTH), which in turn is regulated by the hypothalamic peptides, corticotropin-releasing hormone (CRH) and vasopressin (VP) (2,3). It is clear that reciprocal interactions exist between the HPA axis and vasoactive hormones. For example, the hypothalamic peptides CRH and VP have recognized vasodilator and vasoconstrictor actions, respectively. Also, catecholamines and a number of vasoactive hormones including angiotensin II (Ang II), atrial natriuretic peptide, adrenomedullin and neuropeptide Y, are involved in the regulation of hypothalamic CRH (3). This discussion will address the interactions between some of these vasoactive hormones and different components of the HPA axis, and their physiological implications during stress adaptation.KeywordsAtrial Natriuretic PeptideHypothalamic Pituitary AdrenalACTH SecretionPituitary CorticotrophVasoactive HormoneThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.