Glutathione levels were estimated in different regions of the brain of 21-, 30-, 40-, 42-, 45-day-old and adult female rats. Glutathione content in the cerebral cortex, cerebellum and the brain stem remained almost the same beginning from day 21 to sexually mature adult rats. There is a significant increase in hypothalamic glutathione content reaching a peak at puberty (42 days) and thereafter decreasing to the adult levels. Plasma gonadotropin levels were evaluated at 5 and 15 min after third ventricular injection of 15 and 30 microgram doses of glutathione in ovariectomized steroid-primed rats. Intraventricular injection of either 15 or 30 micrograms dose of glutathione significantly elevated plasma FSH levels. The 15 micrograms dose of glutathione significantly decreased plasma LH levels whereas 30 micrograms dose had no effect. Lower dose of glutathione inhibits LH release and stimulates FSH release whereas the higher dose of glutathione specifically elevates FSH levels without any change in LH levels suggesting a selective FSH releasing action of glutathione.