title: Evidence for autoregulation of growth hormone secretion via the central nervous system.
abstract: The ability of growth hormone (GH() to regulate its own secretion at the level of the central nervous system was examined in chronically cannulated freely-moving rats. Six-hour GH secretory profiles were obtained from 2 groups of rats administered either normal saline or rat GH via the lateral ventricle of the brain. The typical pulsatile pattern of GH secretion was evident in normal saline-treated control rats with most peak GH values > 400 ng/ml. Injection of rat GH (15 microgram/10 microliter) resulted in a significant suppression in amplitude of GH secretory pulses after an interval of 1 hour and plasma GH levels remained markedly depressed for up to 6 h after injection. Peak GH values did not exceed 76 ng/ml during the latter 3 h of the sampling period. These findings clearly demonstrate that GH can regulate its own secretion via a negative feedback system. Furthermore, the results suggest that the central nervous system is an important site of action for GH autoregulation.
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects / Q000502:physiology*; D005246:Feedback; D013006:Growth Hormone / Q000097:blood / Q000378:metabolism* / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D051381:Rats
chemical_list: D013006:Growth Hormone