A NEW BIOASSAY METHOD FOR LUTEINIZING HORMONE DEPENDING ON THE DEPLETION OF RAT OVARIAN CHOLESTEROL

Abstract

SUMMARY A new assay method for luteinizing hormone (LH) activity is described and the criteria for its reliability are assessed. The technique depends on ovarian cholesterol depletion in intact immature rats pretreated with pregnant mare serum gonadotrophin (PMSG) and human chorionic gonadotrophin (HCG). The main advantage of the ovarian cholesterol depletion (OCD) test is its high sensitivity, the assay being approximately five million times more sensitive than the ovarian ascorbic acid depletion (OAAD) method. The chief disadvantage of the technique is its relatively low degree of precision. The LH activity of various gonadotrophin preparations has been determined by the new OCD test. The results obtained agree well with those found by the OAAD method. The extreme sensitivity of the OCD test suggests that it will be eminently suitable for clinical use.