The granular peripolar cell of the human glomerulus: an ultrastructural study.

Normal human kidneys were examined for the presence of granular peripolar cells. The prominent feature of the human peripolar cell was the presence of numerous cytoplasmic membrane-bound granules, which had the appearance of secretory granules. Most of the granules had a homogeneous matrix with no crystalline substructure. We found no examples of exocytosis, but there were many complex invaginations of the cell membrane. The ultrastructural features of the human peripolar cell are those of a secretory epithelial cell.