Down-regulation of neutral sphingomyelinase in androgen-dependent smooth muscle.

Background: During puberty, proliferation of guinea pig seminal vesicle smooth muscle (SVM) is mediated by androgen-induced basal release of norepinephrine (NE), signaling through the post-junctional alpha1-adrenoceptor. In the adult, the SVM is terminally differentiated, such that cell number is androgen resistant. Sphingomyelinase activation generates second messenger ceramides, which in vascular smooth muscle have been reported to counter the alpha1-adrenoceptor-mediated contractile response and activate apoptosis.