REPEATED INTRACEREBROVENTRICULAR ADMINISTRATION OF TAURINE LOWERS LH LEVELS AND POSTPONES VAGINAL OPENING IN PERIPUBERTAL FEMALE RATS

We investigated the effect of repeated intracerebroventricular injections of taurine (Tau, 0.15 mu mol/3 mu l distilled water), administered during postnatal days 23-29, on serum LH levels, and on the hypothalamic content of LHRH and amino acid neurotransmitters (measured by HPLC and electrochemical detection) in 30-day-old female rats (n = 18). Treatment with Tau lowered serum LH (Tau: 0.20 +/- 0.04; Controls: 1.04 +/- 0.21 ng/ml RP3; mean +/- S.E.M.; P < 0.05) as well as hypothalamic LHRH levels (Tau: 82.6 +/- 9.5; Controls: 128.7 +/- 14.1 pg/mg wet tissue, P < 0.05). Tau treatment doubled hypothalamic GABA levels (Tau: 31.3 +/- 2.9; Controls: 15.6 +/- 1,2 nmoles/mg wet tissue, P < 0.001). In a second group of animals (n = 13), Tau treatment delayed vaginal opening by more than 2 days (P < 0.05 vs. controls). It is concluded that supplementation with Tau during the fourth postnatal week reduces LHRH/LH secretion and postpones sexual development, perhaps by increasing the activity of the hypothalamic GABAergic system.