Depletion of Pituitary Thyrotropic Hormone by Thyrotropin Releasing Factor

Abstract

Intravenous administration of a highly purified preparation of bovine or porcine thyrotropin releasing factor (TRF) produced a significant depletion of pituitary TSH content in mice. The minimum active dose of TRF required for significant TSH depletion is 4 ng. Pretreatment of the mice with 10 [mu]g of L-thyroxine prevented the release and depletion of pituitary TSH after the administration of TRF. Lysine vasopressin and cerebral cortex extracts had no effect on pituitary TSH. Administration of histamine did not lower pituitary. TSH content. These data provide demonstration of the biological activity of TRF.