Follicle-Stimulating Hormone-Releasing Activity in Peripheral Blood

Abstract

Peripheral blood from normal and hypophysectomized rats was examined for FSH-RF activity. Assays for FSH-RF activity consisted of measurement of depletion of FSH in the pituitaries of normal male rats or castrated rats pretreated with testosterone propionate (TP). FSH-RF activity was found in plasma of male rats hypophysectomized for 1 or 2 months but not for 3 months. FSH-RF activity was diminished after elimination of cranial circulation. It was not affected by administration of 1 mg FSH over a 5-day period. No FSH-RF activity was detected in peripheral blood or plasma of normal rats of either sex or male rats hypophysectomized 10 days previously or female rats hypophysectomized 10, 30, 60 or 90 days previously, or in the peripheral blood of hypophysectomized and gonadectomized rats. (Endocrinology81: 1226, 1967)