Phenylephrine (PE) induced vasoconstriction of resistance-sized mesenteric arteries from SHR and WKY testosterone-manipulated males. Data are expressed as percentage maximum constriction (means ± SEM). (A) Mesenteric arteries from spontaneously hypertensive castrate plus testosterone (SHR CAST + T) males demonstrated decreased phenylephrine (PE) constriction compared to SHR control (SHR CONT) rats (*P < 0.05) and SHR CAST rats (†
P < 0.01). (B) Mesenteric arteries from WKY CAST + T males displayed increased PE constriction compared to WKY CONT rats (*P < 0.05).