Involvement of growth hormone-releasing factor in growth hormone secretion induced by gamma-aminobutyric acid in conscious rats.
Intracerebroventricular (icv) injection of gamma-aminobutyric acid (GABA) (10 mumol/rat) resulted in an increase in plasma GH in conscious freely moving rats pretreated with normal rabbit serum (0.5 ml/rat, iv). Rabbit antiserum specific for rat GH-releasing factor (GRF) (0.5 ml/rat, iv) abolished GH release induced by GABA in these animals. Rabbit anti-rat GRF serum also blunted GH release induced by a Met5-enkephalin analog, FK33-824 (10 micrograms/100 g BW, iv) in conscious rats. Considering our previous findings that rat GH release induced by FK33-824 was blunted by GABA antagonists (Endocrinology 103:1033, 1981), these results suggest that GH secretion induced by opioid peptides via GABAergic mechanisms is mediated, at least in part, by hypothalamic GRF in the rat.
D000818:Animals; D002552:Cerebral Ventricles / Q000187:drug effects / Q000502:physiology*; D003243:Consciousness / Q000187:drug effects; D013006:Growth Hormone / Q000378:metabolism*; D013007:Growth Hormone-Releasing Hormone / Q000276:immunology / Q000502:physiology*; D007106:Immune Sera; D007276:Injections, Intraventricular; D007700:Kinetics; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D005680:gamma-Aminobutyric Acid / Q000008:administration & dosage / Q000494:pharmacology*
D007106:Immune Sera; D005680:gamma-Aminobutyric Acid; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone