Effect of Estrogen and Progesterone on Urodynamics in the Conscious Rat

Objectives To examine the effects of estrogen and/or progesterone on the cystometric profiles obtained using continuous-filling cystometry in the conscious Sprague-Dawley rat. Methods Sprague-Dawley rats underwent ovariectomy (OVX) and were compared with controls by conscious continuous-filling cystometry. The effect of estrogen (10 μg/kg/d for 14 days) and/or progesterone (10 mg/kg/d for 14 days) replacement on OVX urodynamics was examined (n = 7-8/group). Results OVX rats demonstrated reduced micturition intervals and voided volumes compared with controls. These effects of OVX were reversed by estrogen replacement, but not by progesterone replacement. When combined with estrogen, progesterone functioned to partially antagonize the effects of estrogen in OVX rats. Conclusions Estrogen enhances bladder capacity in the OVX rat and therefore is a likely contributor to the larger bladder capacity in the female compared with the male rat. Consistent with its established role in reproductive physiology, progesterone antagonizes the beneficial effects of estrogen on OVX rat urodynamics.