%0 Journal Article %T Differential effects of androgens on coronary blood flow regulation and arteriolar diameter in intact and castrated swine %A Erin K O'Connor %A Jan R Ivey %A Douglas K Bowles %J Biology of Sex Differences %D 2012 %I BioMed Central %R 10.1186/2042-6410-3-10 %X Pigs received intracoronary infusions of physiologic levels (1¨C100 nM) of testosterone, the metabolite 5¦Á-dihydrotestosterone, and the epimer epitestosterone while left anterior descending coronary blood flow and mean arterial pressure were continuously monitored. Following sacrifice, coronary arterioles were isolated, cannulated, and exposed to physiologic concentrations (1¨C100 nM) of testosterone, 5¦Á-dihydrotestosterone, and epitestosterone. To evaluate effects of the androgen receptor on acute androgen dilation responses, real-time PCR and immunohistochemistry for androgen receptor were performed on conduit and resistance coronary vessels.In vivo, testosterone and 5¦Á-dihydrotestosterone produced greater increases in coronary conductance in the intact compared to the castrated males. In vitro, percent maximal dilation of microvessels was similar between intact and castrated males for testosterone and 5¦Á-dihydrotestosterone. In both studies epitestosterone produced significant increases in conductance and microvessel diameter from baseline in the intact males. Androgen receptor mRNA expression and immunohistochemical staining were similar in intact and castrated males.Acute coronary vascular responses to exogenous androgen administration are increased by endogenous testosterone, an effect unrelated to changes in androgen receptor expression. %K Androgens %K Coronary blood flow %K Porcine %K Vasomotor %K Androgen receptor %U http://www.bsd-journal.com/content/3/1/10/abstract