The effects of gamma-aminobutyric acid on prolactin and gonadotropin secretion in the unanesthetized rat.

The effects of the intraventricular injection of gamma-aminobutyric acid (GABA) on pituitary secretion of luteinizing hormone (LH), follicle stimulating hormone (FSH), and prolactin (PRL) were examined in Na-pentobarbital (PB)-anesthetized and unanesthetized male rats. GABA (5 or 10 millimicronmol) injected into the lateral ventricle of PB anesthetized rats resulted in significant elevations in plasma concentrations of LH and PRL. When administered via a lateral ventricle cannula to unanesthetized rats, GABA (1, 5, or 10 millimicronmol) caused a significant increase in plasma PRL levels but had no effect on plasm LH concentrations. Plasma FSH was uninfluenced by GABA in all animals studied. The data indicate that PB anesthesia can alter the hypothalamic pituitary axis to a possible neurotransmitter agent.