Regulatory influences of hypothalamic suprachiasmatic nucleus on the endocrine system

Bulgarian Medical Journal, 2025, 19(4), 7-11.

N. Stoynev

Department of Physiology and Pathophysiology, Medical Faculty, Medical University – Sofia

Abstract. Suprachiasmatic nucleus, well known as circadian pacemaker, still remains much less studied as participant in homeostatic regulation. The aim of this review is to summarize the scarce data about its influence on hormone secretion and hormone response outside the context of the circadian rhythms. Suprachiasmatic nucleus has an impact on vasopressin response to water deprivation, dehydration, rehydration and hyperosmotic stimuli. The secretion of raptin, recently identified hormonal factor with an influence on food intake and on body weight balance, depends on the arginin-vasopressin producing neurons in the suprachiasmatic nucleus. Suprachiasmatic nucleus has an influence on the hormonal regulation of plasma glucose, the acute adrenocorticotropic response in stress, the maintenance of basic level of melatonin secretion, the secretion of growth hormone, the secretion of thyrotropic hormone and the gonadotropic axis. Conclusions: Suprachiasmatic nucleus has a role in the homeostatic regulation of hormone secretion of some endocrine glands outside the context of the circadian rhythms.

Key words: suprachiasmatic nucleus, hormone secretion, raptin, vasopressin

Address for correspondence: Nikolay Stoynev, MD, PhD, e-mail: nstoynev@medfac.mu-sofia.bg