The Effects of γ-Aminobutyric Acid on Prolactin and Gonadotropin Secretion in the Unanesthetized Rat

Abstract

The effects of the intraventricular injection of GABA on pituitary secretion of luteinizing hormone (LH), follicle stimulating hormone (FSH) and prolactin (PRL) were examined in sodium pentobarbital (PB)-anesthetized and unanesthetized male rats. GABA (5 or 10 .mu.mol) injected into the lateral ventricle of PB anesthetized rats significantly elevated plasma concentrations of LH and PRL. When administered via a lateral ventricle cannula to unanesthetized rats, GABA (1, 5, or 10 .mu.mol) significantly increased plasma PRL levels but had no effect on plasma LH concentrations. Plasma FSH was uninfluenced by GABA in all animals studied. PB anesthesia can probably alter the response of the hypothalamic pituitary axis to a possible neurotransmitter agent.