FSH and LH of the Pituitary Gland of Gonadectomized Snowshoe Hares1

Experiments were designed to examine effects of bilateral gonadectomy on pituitary FSH and LH and serum LH of snowshoe hares (Lepus americanus) during the breeding season. Male and female hares were gonadectomized and then sacrificed at 10-, 20-, 30-, 45- and 60–day intervals, and the pituitaries were assayed for LH and FSH using modifications of the Parlow Ovarian Ascorbic Acid Depletion Assay (OAAD) and Steelman and Pohley HCG augmentation assays, respectively. In both males and females, pituitary LH and FSH increased progressively between the 10th and 60th day after gonadectomy. By the 60th day pituitary LH in the female had increased to 3 times that observed in the male; however, the male pituitary contained more FSH. Serum LH increased dramatically to the 20th day, and continued to increase at a much slower rate thereafter. (Endocrinology92: 344, 1973)