Could α1-adrenoceptors and androgen receptors be modified by sexual maturation and testosterone in the rat testicular capsule?

Abstract Aims Testicular capsule contractile dysfunctions are recognized to contribute to male infertility, but the influence of sexual maturation and exogenous testosterone on the expression and function of androgen receptor and α 1 -adrenoceptors on rat testicular capsule is unclear. Here, these two biological parameters were evaluated on testicular capsule from sexually immature and young adult rats treated or not with exogenous testosterone. Main methods Male Wistar rats (45- and 60-day-old) were assigned into groups: control (saline 0.9%) or testosterone-treated (propionate testosterone). Testicular capsule was isolated and processed for functional studies, immunohistochemistry, Western blot and RT-PCR studies. Key findings Relative testicular capsule wet weight was not affected by sexual maturation or exogenous testosterone treatment. The expression and immunolocalization of androgen receptor (mRNA and protein) was identified in testicular capsule. Androgen receptor and α 1 -adrenoceptor ( Adra1a , Adra1b , and Adra1d ) mRNA levels were similar in testicular capsule from all experimental groups. Functional studies indicated that contractions produced by noradrenaline in testicular capsule from 45- and 60-day-old rats treated or not with testosterone were mainly mediated by α 1A - and α 1B -adrenoceptors. The L-type Ca 2 + channel blocker nifedipine induced a higher inhibitory effect on noradrenaline induced contractions in testicular capsule from 45- than 60-day-old rats treated with testosterone. Significance Molecular studies, immunohistochemistry and pharmacological functional assays used in this study provide evidences of the androgen receptor expression in testicular capsule and that function, and not mRNA and protein expression levels of the α 1 -adrenoceptor subtypes in this tissue, is differentially influenced by the rat androgen status.