The replenishment of the juxtaglomerular renin store after temporary renin depletion

Abstract

Renal cortical and plasma renin activities and the electron microscopic appearance of juxtaglomerular epitheloid cells were investigated in the unclamped renin-depleted kidney of rats with two-kidney-Goldblatt hypertension after removal of the clamped kidney. Within 24 h the renal renin content fell to still lower values, on the 2d day, it rose to one half its normal value, on the 7th day it reached its control value. Renin activity of plasma did not significantly differ from zero until the 3d day after removing the clamped kidney, reached 20% of normal on the 7th day and normal values between the 7th and the 21 st day. Sparse secretory granules appeared in the remaining renal cortex 12 h after removal of the clamped kidney. After 24 h secretory granules were formed by confluence of Golgi vesicles. After 2 days cisternae appeared in the rough-surfaced endoplasmic reticulum. After 4 days the electron-microscopic picture became normal. Renin appears to be elaborated in the rough-surfaced endoplasmic reticulum and concentrated into granules by the Golgi-apparatus. A fraction of the renal renin does not appear to be available for secretion.