THE EFFECT OF 6 m UREA ON THE FOLLICLE-STIMULATING AND LUTEINIZING HORMONE ACTIVITIES OF VARIOUS GONADOTROPHIN PREPARATIONS

Abstract

SUMMARY: The luteinizing hormone (LH), follicle-stimulating hormone (FSH) and 'total gonadotrophic' activities of various hormones have been studied following incubation with 6 m urea at 40° c for 24 hr. LH activity was estimated by the ovarian ascorbic acid depletion test in rats, FSH activity by the augmentation test in mice, and 'total gonadotrophic' activity by the mouse uterus test. Following incubation with 6 m urea the LH activities of NIH—LH, NIH—FSH, human chorionic gonadotrophin and Pergonal were almost completely destroyed, while the LH activity of pregnant mares' serum gonadotrophin (PMSG) was reduced to a smaller extent. The FSH activity of NIH—FSH was little affected by this form of treatment, but in the case of Pergonal a considerable reduction of FSH activity occurred. The 'total gonadotrophic' activity of NIH—FSH, PMSG and Pergonal was reduced after incubation with 6 m urea, the degree of inactivation being greatest in the case of Pergonal. After control incubations with water no appreciable loss of biological activity was observed with any hormone other than Pergonal.