[Substrate specificity of peptidases catalyzing LH-RH degradation in hypothalamus, liver and heart of rat].

Degradation of [125I]-LH-RH by peptidases of hypothalamus, liver and heart of the rat and the effects of LH-RH, LH-RH antagonist D-Phe2-Phe3-D-Phe6-LH-RH, LH-RH5-10, oxytocin, bradikinin, thyrotrophin-releasing hormone, melanocyte-inhibiting factor, luteinizing, follicle-stimulating, lactogenic and growth hormones were studied. It was shown that the degradation was inhibited with maximal efficiency by non-labelled LH-RH (Ki = 1,7--2,0 . 10(-6) M). This observation is indicative of peptidase specificity for LH-RH. It is assumed that specific peptidases of liver and heart are involved in the reglation of LH-RH concentration in these organs.