Extra-renal transcription of the renin genes in multiple tissues of mice and rats.

Expression of the mouse renin genes (Ren-1 and Ren-2) and of the unique rat renin gene was determined in several extra-renal tissues of mice and rats by primer-directed enzymatic amplification of cDNAs. In addition to the adrenal glands, testis, and ovaries, renin transcripts are detected in the liver, whole brain, and hypothalamus and, at lower levels, in spleen, thymus, lung, and prostate. Expression of the rat renin gene correlates with that of the mouse Ren-1 gene with the notable exception of the submaxillary gland where renin transcripts are found only in mice. The levels of renin transcripts in the liver of females from both species are higher than in males. In mice, the relative levels of Ren-1 and Ren-2 transcripts vary widely in different tissues. These results support the hypothesis of a local renin-angiotensin system in multiple extra-renal sites and imply the existence of complex mechanisms of regulation of the renin gene, previously thought to be expressed in a tissue-specific manner.