A COMPARISON OF THE BIOLOGICAL ACTION OF ALLOPREGNANE-21-OL-3,20-DIONE ACETATE AND PROGESTERONE1

Abstract

A comparison of allopregnane-21-ol-3,20-dione acetate with progesterone on the basis of the well-known actions of the latter compound in (a) inhibiting the estrogen-induced growth of the chick oviduct, (b) progestational activity in the rabbit uterus, (c) deciduoma formation in the rat uterus, (d) suppression of pituitary gonadotropin in parabiotic rats and (e) prevention of withdrawal bleeding in estrogen-primed castrate female monkeys, has demonstrated that inhibition of chick oviduct growth is the only action common to the 2 steroids. Moreover, allopregnane-21-ol-3,20-dione acetate was found to be 2-4 times as potent as progesterone in the oviduct assay. Thus, inhibition of the oviduct in the estrogen-treated chick may be clearly dissociated from other biological actions of progesterone.