Effect of taurine on growth hormone and prolactin secretion in rats: possible interaction with opioid peptidergic system.

Abstract The effect of taurine on growth hormone (GH) and prolactin (PRL) secretion was investigated in the urethane-α-chloralose anethetized rats, considering the interaction with endogenous opioid peptidergic system. Intraventricular injection of taurine (0.25 and 1.0 μmol) stimulated GH and PRL secretion in a dose-dependent manner. However, 4.0 μmol taurine failed to show these effect. The intravenous infusion of naloxone (4 mg/kg b.w.) completely inhibited both the GH and PRL secretion induced by taurine (1.0 μmol). The combined treatment of taurine (1.0 μmol) and FK33-824 (Met-enkephalin derivative, 100 μg/kg b.w., i.v.) significantly increased GH and PRL responses induced by taurine or FK33-824 alone. These results indicate that taurine is an effective stimulator of GH and PRL secretion in rats, and that the mechanism of this action involves the opioid peptidergic system in the hypothalamus.