Myogenic reactivity of resistance-sized mesenteric arteries from spontaneously hypertensive and Wistar Kyoto testosterone-manipulated male rats. Myogenic reactivity is expressed as percentage change in diameter from an initial diameter at 20 mmHg. Only 60- to 120-mmHg pressure points are expressed in the graphs (means ± SEM). (A) Mesenteric arteries from spontaneously hypertensive control (SHR CONT) males displayed increased myogenic reactivity compared to SHR castrate plus testosterone (CAST + T) (*P < 0.05). (B) Mesenteric arteries from Wistar Kyoto (WKY) CAST + T rats displayed increased myogenic reactivity compared to WKY CONT rats (*P < 0.05).