Evidence for lysosomal matrix in the juxtaglomerular cell granules.

A systematic histochemical analysis of the matrix composition of juxtaglomerular cell granules was carried out. The behaviour of kidney lysosomes under similar conditions has been examined in parallel. The tubular protein droplets produced by the i.p. administration of egg albumen were chosen as lysosome-model. Identical pattern of histochemical reactions has been demonstrated both in kidney lysosomes and juxtaglomerular granules indicating the presence of separate lipoprotein and glycoprotein components. The ammoniated silver carbonate method for lysosomes was also positive in juxtaglomerular cell granules. These results support on a non-enzymatic basis the concept that secretory granules and lysosomes are evolutionary homologues.