EXPERIMENTAL STUDIES ON THE EFFECT OF ERGOCORNINE METHANESULPHONATE ON THE LUTEOTROPHIC FUNCTION OF THE RAT PITUITARY GLAND

Abstract

The effects of a single administration of 1 mg ergocornine methane-sulphonate to female rats with functional corpora lutea have been studied. It was shown that (1) Injection of ergocornine into hypo-physectomized rats bearing an autotransplanted pituitary brought about morphological changes in the corpora lutea; (2) In intact rats bearing two isologous pituitaries a prolonged period of leucocytic vaginal smear was found following an ergocornine-induced oestrus, indicating that the secretion of luteotrophic hormone was resumed after drug treatment; (3) Administration of ergocornine to lactating rats temporarily inhibited milk production, the effect being prevented by treatment with luteotrophic hormone. These studies indicate that the effects of ergocornine administration to intact female rats such as failure to develop decidual tissue as a response to uterine traumatization and the interruption of the leucocytic vaginal smear by oestrus, are the result of a temporary inhibition of the secretion of luteotrophic hormone by the pituitary. This brings about irreversible changes in the corpus luteum. The subsequent progesterone deficiency is responsible for the failure of the decidual tissue to develop and for the onset of oestrus three days after the administration of the drug.