DIRECT PROGESTATIONAL ACTION OF PROGESTERONE AND CERTAIN RELATED STEROIDS ON THE ENDOMETRIUM OF THE RHESUS MONKEY

Abstract

SUMMARY: Solid intrauterine implants of certain steroids were made in prepubertal and adolescent ovariectomized and oestrone-primed rhesus monkeys. Implants of the following steroids produced localized progestational changes in the endometrial glands: progesterone, deoxycortone, ethisterone, testosterone, methyl testosterone and methyl dihydrotestosterone. Pregnenolone produced only minimal progestational effects. Pregnanediol showed no progestational effect and failed to maintain the endometrium. A comparison of the direct progestational action of a number of steroids on the endometrium has been made in the four species so far investigated (mouse, rabbit, cat and monkey, each of which represents a different mammalian order). Direct progestational action requires a fairly close structural similarity to progesterone in all cases, but the degree of similarity required shows a marked species difference.