28 November 2008
Epitheloid cells of afferent arterioles, Granulation of juxtaglomerular cells, Renal cortical renin activity in the guinea pig, rat, and man, Extragranular renin, Mechanism of juxtaglomerular granule formation
In the normal guinea pig, the rennin activity of renal cortical tissue was one tenth of that of the rat. Light microscopy did not reveal juxtaglomerular granules in epitheloid cells, while electron microscopy showed very rare small and pale granules. In adrenalectomized animals, cortical rennin activity increased fourfold 8–12 days after operation. Granules increased more than tenfold and were larger and darker; the rough-surfaced endoplasmic reticulum expanded. Data suggest that normal guinea pig kidney may contain extragranular cytoplasmatic renin, while larger amounts of renin occurring after adrenalectomy are deposited in newly formed granules.