Appearance of dense granules in the rough endoplasmic reticulum of the juxtaglomerular cells in mice administered with captopril.

Captopril [1-(D-3-mercapto-2-methyl-1-oxopropyl)-L-proline (S,S)] is now known to be an inhibitor of angiotensin-converting enzyme. In male mice, the juxtaglomerular cells were examined by electron microscopy 42 h after administration of captopril. Numerous dense granules appeared in the rough endoplasmic reticulum of these cells.