THE RÔLE OF GONADOTROPIC HORMONE IN THE MAINTENANCE OF LUTEAL FUNCTION

¹ Department of Pharmacology, University of Edinburgh

Pseudo-pregnant rabbits were hypophysectomized and the luteal function was maintained for 3 days by the administration of strin. Gonadotropic hormone from human pregnancy urine was then injected in doses which maintain the luteal function when given to pseudopregnant animals immediately after hypophysectomy, but it failed to maintain the luteal function.

As it has been previously shown that the capacity of the ovary to respond to stimulation by gonadotropic hormone rapidly decreases after removal of the pituitary, it is suggested that the failure of gonadotropic hormone to maintain the luteal function in the present experiments is due to its failure to induce strin secretion by the ovary, and that normally gonadotropic hormone controls the luteal function through the secretion of strin and not by any direct action on the corpora lutea. The relevance of these findings to the problem of the existence of one or more gonadotropic hormones is discussed.

When strin is injected into rabbits in which ovulation has been induced after hypophysectomy, active corpora lutea develop.

The synthetic strogenic substance triphenyl ethylene can maintain the luteal function in hypophysectomized rabbits.

The expenses of this research were defrayed by a grant from the Medical Research Council.