Renin and angiotensin II receptor gene expression in kidneys of renal hypertensive rats
Haefliger, J.A.; Bergonzelli, G.; Waeber, G.; Aubert, J.F.; Nussberger, J.; Gavras, H.; Nicod, P.; Waeber, B.
Hypertension 26(5): 733-737
1995
ISSN/ISBN: 0194-911X PMID: 7591011 Document Number: 446377
The aim of this investigation was to examine the interrelation between renal mRNA levels of renin and angiotensin II receptor type 1 (AT-1) in a renin-dependent form of experimental hypertension. Rats were studied 4 weeks after unilateral renal artery clipping. Mean blood pressure and plasma renin activity were significantly higher in the hypertensive rats (n = 10 206+-8 mm Hg and 72.4+-20.9 ng cntdot mL-1 cntdot h-1, respectively) than in sham-operated controls (n = 10, 136+-3 mm Hg and 3.3+-0.5 ng cntdot mL-1 cntdot h-1 respectively). Northern blot analysis of polyA+ RNA obtained from the kidneys of renal hypertensive rats showed increased levels of renin mRNA in the clipped kidney, whereas a decrease was observed in the unclipped kidney. Plasma renin activity was directly correlated with renin mRNA expression of the poststenotic kidney (r = .94, P lt .01). AT-1 mRNA expression was lower in both kidneys of the hypertensive rats. This downregulation was specific for the AT-1A subtype since the renal expression of the AT-18 subtype remained normal in hypertensive rats. The downregulation of the renal AT-1A receptor may be due to high circulating angiotensin II levels. This is supported by the significant inverse correlation (r = -.71, P lt .01) between plasma renin activity and AT-1A mRNA expression measured in the clipped kidney of the hypertensive rats.