Stimulation of LH and FSH secretion following intraventricular injection of cysteic acid but not taurine

Abstract Taurine and related neurally active metabolites, were tested for their ability to influence basal secretion (FSH). The animal model used was the unanesthetized, unrestrained adult rat with an indwelling catheter in the jugular vein and a cannula implanted in the right lateral cerebroventricle or anterior pituitary. The proposed inhibitory neurotransmitter taurine, and its metabolic precursor, hypotaurine, did not affect the secretion of LH of FSH following infusion of 0.2 or 2.0 μmol intraventricularly or into the pituitary. In contrast, intraventricular injection of cysteic acid, a neurally excitant amino acid, in doses of 2.0 and 0.2 μmol promoted pituitary secretion of LH in both male and female rats. FSH secretion was also increased slightly by cysteic acid (2.0 μmol). These studies provide additional evidence that excitatory amino acids have a stimulatory role in the release of pituitary gonadotropins.