Time-related effects of monosodium glutamate on the reproductive neuroendocrine axis of the hamster.

Abstract

Monosodium glutamate (MSG) was used to produce a lesion in the arcuate nucleus (ARC) of the hypothalamus in the neonatal hamster. In Exp I, hamsters were given a single sc injection of saline or 8 mg MSG/g BW on days 1-15 of the neonatal period. The severity of the lesion was measured by studying the percentage of neurons in the ARC that were morphologically intact 6 h after the injection. There was a decline in the percentage of intact neurons from 82% in animals given MSG on day 1 to 14–19% in those injected on days 7–11. There was an increase in the percentage of intact neurons in the ARC to 71% by day 15. In Exp II, female hamsters were treated with saline or MSG in a similar manner on days 4-15 of the neonatal period. The animals were sacrificed as adults at approximately 2 months of age and the following parameters were studied: the severity of the lesion in the ARC, the occurrence and regularity of estrous cycles, ovarian histology, weights of the anterior pituitary glands, and the concentrations o...