1. Using a ribonuclease-protection assay, renin mRNA levels were compared in the kidneys, livers, brains, hearts and adrenal glands of two-kidney, one-clip Goldblatt hypertensive rats with those of age-matched control rats at 4 weeks (‘early’) and 20 weeks (‘chronic’) after clipping, and in the kidneys and adrenal glands of rats treated for 3 weeks with deoxycorticosterone and salt (deoxycorticosterone-salt hypertension) with those of control rats.
2. While marked changes were observed in kidney renin mRNA levels in all three experimental groups compared with their respective controls, in most of the extrarenal tissue studied minimal, if any, difference was seen in renin mRNA levels between the hypertensive and control rats.
3. The findings suggest that in these extra-renal tissues renin gene expression is differently regulated from that in the kidney, and particularly that it is not profoundly affected by changes in the level of circulating angiotensin II.
4. An increase in renin mRNA was observed in the adrenal glands of the ‘chronic’ Goldblatt rats, which may be of relevance to the maintenance of hypertension in this model.