OVARIAN ANDROSTENEDIONE PRODUCTION IS ENHANCED BY INSULIN DURING THE PERIOD OF DELAYED OVULATION IN A VESPERTILIONID BAT, SCOTOPHILUS-HEATHI

The aim of the present study was to evaluate the role of insulin in th e production of high concentrations of androstenedione in the ovary of Scotophilus heathi during the period of delayed ovulation. The concen trations of serum insulin were found to be high during November and De cember and declined significantly before ovulation. A significant corr elation was observed between circulating insulin concentration and bod y weight as well as with serum androstenedione concentrations. Autorad iographic study demonstrated specific accumulation of I-125-labelled i nsulin in the ovarian thecal and interstitial cells. Insulin increased both basal and hCG-stimulated androstenedione production by the ovary in vitro during November. These results indicate that insulin may be involved in inducing high androstenedione synthesis by the ovary and t hus may be indirectly responsible for inducing delayed ovulation in S. heathi.