Differences in kidney renin content between normotensive and spontaneously hypertensive rats: effect of captopril treatment.

Kidney renin concentrations were significantly lower in spontaneously hypertensive rats (SHR) than in normotensive Wistar Kyoto (WKY) rats. After treatment of both SHR and WKY rats with captopril (100 mg/kg p.o. for 3 months), kidney renin concentration increased dramatically in SHR and slightly, but significantly, in WKY. After captopril treatment, kidney renin content of SHR was still significantly lower than WKY. Because of the lower content of kidney renin in SHR and the proportionately greater increase in kidney renin content in SHR after captopril treatment than in WKY, it is proposed that a fundamental difference(s) in the control of the renin-angiotensin system exists in SHR, an effect which may or may not be related to SHR hypertension.