Failure of exogenous gonadotrophin controlled ovulation to cause digit abnormalities in mice

Abstract

GONADOTROPHINS have been used for many years in laboratory work to induce ovulation in animals at specific convenient times^1–5. An injection of pregnant mare serum (PMS) induces follicular growth, and if this is followed by an injection of human chorionic gonadotrophin (HCG) the mature follicles are ovulated at a predictable time. There are a few suggestions in the literature that this practice may lead to abnormalities in the offspring of the treated females^6–8. In particular, Elbling⁸ reported that abnormalities in the digits and an altered sex ratio were found in litters born to gonadotrophin-treated female mice. As the practice of inducing ovulation by these means is widespread in research and is of practical importance in swine husbandry, we felt that this claim against PMS and HCG should be evaluated. We therefore repeated part of the experiment performed by Elbling⁸, with slight modifications, in that we did not study postnatal survival but observed digit normality, sex ratio and litter size in two stocks of mice in an effort to detect the influence that different genetic backgrounds may have in the response to exogenous gonadotrophins. We found no abnormalities in the digits or altered sex ratio in the offspring.