[Orientation studies of ovulation release in mice to test gonadotropic preparations. 1. Dosage of PMSG and HCG]

Reported in this paper are the authors' own experience and results concerning a method of testing ovulation in mice by which activities of gonadotrophic preparations can be determined. Prepuberal female mice received as pretreatment a subcutaneous injection of 0.5 or 1.0 IU of PMSG (pregnant mare serum gonadotrophin) per animal. When HCG (human chorionic gonadotrophin) ws subcutaneously injected, 48 hours later, ovulation was induced in all animals and could be microscopically counted between two glass slides under slight pressure, after another 18 hours had elapsed. The highest effective dose (ED100) in most of 40 comparisons was close to 1.0 IU of HCG. Dosages of 0.2, 0.4, 0.6, 0.8, and 1.0 IU of HCG were found to be suitable for effective dosage determination. Differences in action between various batches of lyophilised HCG were elucidated by using two variables, a threshold reached when three of five animals in one and the same dosage group had ovulated, and ED100, when all had ovulated.