Histochemistry and Ultrastructure of the Juxtaglomerular Apparatus in Magnesium-Deficient Rats

Abstract

The activity of glucose-6-phosphate dehydrogenase and of 6-phosphogluconate dehydrogenase at the level of the macula densa as well as the ultrastructure of the juxtaglomerular apparatus have been studied in magnesium-deficient rats and the results correlated with changes in hematocrit and hemoglobin values, in number of red blood cells, and in systemic blood pressure. The results indicate that magnesium deficiency induces hyperplasia and hypertrophy of epithelioid juxtaglomerular cells without any increase in the enzymatic activity of the macula densa. The ultrastructure of lacis cells is not altered while slight modifications are noted in the cells of the macula densa. These changes are ascribed to systemic hypotension and possibly to hypoxia.