Effects of ovarian hormones on beta-adrenergic receptor-mediated relaxation in the female rabbit bladder

The effects of ovarian hormones on beta-adrenergic receptor-mediated respon ses in female rabbit detrusor smooth muscles were investigated. Ovariectomi zed mature female New Zealand white rabbits were untreated or treated with estrogen and/or progesterone for 2 weeks. The contractile responses to carb achol and KCI in the detrusor strips were not significantly different in al l groups. As compared with dobutamine and GS-332, isoproterenol and procate rol significantly relaxed the detrusor strips derived from all groups on KC l-induced tonic contractions. Combined with estrogen treatment, isoproteren ol, procaterol and GS-332 caused a significant increase in this muscle rela xation. Furthermore, estrogen treatment caused a significant increase in re laxation as a result of forskolin and the cyclic AMP (cAMP) production that was induced by isoproterenol, procaterol and GS-332. However, estrogen tre atment. did not affect the relaxant response to dibutyryl cyclic AMP. Proge sterone treatment did not affect beta-adrenergic receptor-mediated response s. These results suggest that estrogen treatment causes the increased relax ant responses mediated by beta(2)-and beta(3)-adrenergic receptor subtypes, which may be related to the increased cAMP content in female rabbit detrus or smooth muscles.