THE PRESENCE OF PEPTIDASES IN THE RAT HYPOTHALAMUS INACTIVATING LUTEINIZING HORMONE RELEASING HORMONE (LH-RH)

Abstract

The presence of peptidases in the rat hypothalamus inactivating luteinizing hormone-releasing hormone (LH-RH) has previously been demonstrated using an indirect assay method. With the development of a sensitive and specific radioimmunoassay for the releasing hormone, this technique was employed in the study of the peptidases inactivating LH-RH. It was found that supernatant fractions from both male and female rat hypothalami rapidly inactivated LH-RH, and that the peptidase activity of the supernatant fraction was higher in male than in female animals though the particulate fraction's activity was about the same in both sexes. Peptidase activity was also considerably greater in the supernatant than in the particulate fraction. These results confirm that the hypothalamus contains peptidases capable of inactivating LH-RH and give a direct indication that the enzymes may be involved in the central nervous system's control of reproductive function.