Maintenance of decidual cell reaction by androgens in the mouse

In the mouse, estrogen and progesterone are required to prime the uterus for decidual cell reaction (DCR) in response to an intraluminal stimulus and, once DCR is induced, progesterone is required to maintain DCR. However, some evidence indicates that certain nonprogestational steroid hormones may also be involved in regulating DCR. The present study determined whether androgen plays any role in DCR. Adult CD1 mice were ovariectomized and treated with a regimen of estradiol and progesterone to prime the uterus for DCR and to maintain DCR. Sesame oil was injected into the uterine lumen to induce DCR on Day 5 of the treatment. DCR was determined by deciduomal weight-the difference between the wet weights of oil-injected and noninjected uterine horns. Testosterone, given at 1 mg/day during Days 3-5, could not replace progesterone in priming the uterus for DCR. However, the same dose of testosterone given during Days 6-8 maintained DCR. Alkaline phosphatase activity, a bio-marker for DCR, was present in the deciduoma maintained by either progesterone or testosterone, although the distribution of this enzyme activity was more intense in the antimesometrial pole in progesterone-maintained deciduoma. A nonaromatizable androgen, 5 alpha-dihydrotestosterone (DHT), was also effective in maintaining DCR, and this action of DHT was blocked by an androgen receptor antagonist, hydroxyflutamide. The relative potency of DHT in maintaining DCR was similar to that of progesterone. However, the regression of the deciduoma appeared to be advanced in DHT-treated mice. Ovariectomy on Day 6 of pregnancy resulted in resorption of the conceptus and regression of the decidua within 48 h. Treatment with DHT at the time of ovariectomy could not prevent fetal resorption, but it delayed the regression of decidua, as indicated, in part, by the presence of granulated metrial gland cells. In summary, androgen cannot prime the uterus for DCR, but it can maintain DCR once it is induced. The physiological significance of this finding remains to be determined.