Changes in luteinizing hormone and prolactin control mechanisms produced by glutamate lesions of the arcuate nucleus.

Abstract

Lesions of the arcuate nucleus and retina were produced by ip administration of 4 g/kg monosodium glutamate to rats on days 2,4, 6, and 10 after birth, and all experimental work was continued at about 3–5 months of age. In agreement with earlier studies, we noted a striking reduction in the number of cell bodies in the arcuate nucleus, a marked degeneration of the visual system, and smaller anterior pituitaries, ovaries, uteri, testes, and seminal vesicles in adult rats that had been treated with glutamate during the neonatal period. A 60% reduction in the concentration of dopamine in the medial-basal hypothalamus and irregular estrous cycles also were observed in glutamate-treated groups. In two of six groups of glutamate-treated rats, basal serum LH levels were lower than in controls, whereas in one of six groups, PRL was elevated. The remainder of glutamate-treated groups showed no significant change in basal serum PRL or LH levels. After ovariectomy, serum LH levels were lower in glutamate-treated rat...