DECREASED GONADOTROPHIC HORMONE CONTENT OF THE ANTERIOR PITUITARY GLAND IN DOGS WITH HYPOTHALAMIC LESIONS1,2

Abstract

Assays for interstitial cell stimulating hormone and follicle stimulating hormone activity have been performed on the pituitaries of five male dogs with lesions in the posterior median eminence and the pituitaries of ten castrate male dogs with lesions in various parts of the hypothalamus. All dogs with destruction of the posterior median eminence showed depressed ICSH and FSH values. A lesion in the anterior median eminence in one castrated dog caused a lesser depression of pituitary content of these hormones; other lesions studied had no effect. The presence of a lowered FSH and ICSH content in the pituitary was not correlated with depressed thyroid or adrenal function or with the presence of diabetes insipidus. It is suggested that lesions in the posterior median eminence in the dog selectively inhibit the production and secretion of both ICSH and FSH.