COMPARISON OF PLASMA LEVELS OF LUTEINIZING HORMONE RELEASING HORMONE IN MEN AFTER INTRAVENOUS OR INTRANASAL ADMINISTRATION

Abstract

SUMMARY The concentrations of luteinizing hormone releasing hormone (LH-RH) and luteinizing hormone (LH) were determined by radioimmunoassay in blood samples taken at intervals after the administration of different doses of synthetic LH-RH administered either intravenously or intranasally in healthy fertile men. Intranasal administration of LH-RH caused a dose-dependent increase of plasma LH with the peak occurring later than that after intravenous injection. The intravenous route was approximately 100 times more effective than the intranasal route in terms of the dose of LH-RH necessary to achieve an LH response of similar magnitude, but the route through the nasal mucosa seems a safe and convenient way for LH-RH administration. The characteristics of the disappearance curve, metabolic clearance rate and volumes of distribution of LH-RH in man are compared with those found by others.