Juxtaglomerular cell

Overview
In the kidney, the juxtaglomerular cells (JG cells, also known as granular cells) are cells that synthesize, store, and secrete the enzyme renin. They are specialized smooth muscle cells in the wall of the afferent arteriole that delivers blood to the glomerulus. In synthesizing renin, they play a critical role in the renin-angiotensin system and thus in renal autoregulation, the self-governance of the kidney.

In appropriately stained slides, juxtaglomerular cells are distinguished by their granulated cytoplasm.