Deciduomal Responses in the Uteri of Ovariectomized Golden Hamsters, Comparing Progesterone and Three Closely Related Steroids Applied in utero1

Abstract

Four closely related steroids were tested for their decidualizing effect in uteri of golden hamsters. These compounds were progesterone, 5α-pregnane-3,20-dione (DHP), deoxycorticosterone (DOC) and Δ5-pregnen-3β-ol-20-one (pregnenolone). Intrauterine application was done by dissolving each compound in a semisolid wax-sesame oil mixture and injecting the material intraluminally by means of an 18 gauge trocar. All hamsters were ovariectomized except for 1 group of pseudopregnant controls. Treatment was on Days 1 and 4 after ovariectomy and decidual development was judged on Day 7. All treatments which included progesterone gave the largest deciduomata, including the pseudopregnant group. Both DOC and DHP gave less decidual response, with some DHP uteri merely showing lack of atrophy. Pregnenolone and plain wax gave no response and permitted uterine atrophy after ovariectomy. The relative effectiveness of the several steroids in promoting deciduomata was correlated with their relative binding affinities for uterine progesterone receptor proteins as indicated by previous studies.