Light and electron microscope histochemistry of alkaline phosphatase in the ventral prostate of rats.

Alkaline phosphatase was studied in the ventral prostate of rats by light and electron microscopy. In light microscopy, the enzyme activity was found in the luminal secretion and also on the luminal edge of the acinar walls as well as in the basal area of the acinar walls. It was also found in the walls of periacinar blood capillaries. The enzyme activity was abolished with addition of either L-phenyl-alanine or L-homoarginine and also of L-tartaric acid into the incubating medium. In electron microscopy, the enzyme activity was observed in the luminal secretory material and further it was observed strongly in the sharply localized pittings of apical surface of acinar secretory epithelial cells. The lower lateral and basal surface of the cells showed presence of rather weak activity of the enzyme. The basal cells showed strong activity of the enzyme in pinocytotic vesicles. Further, intense activity of the enzyme was observed on the cell surface of the fibrocytes immediately surrounding acinar basal lamina and also in pinocytotic vesicles of periacinar blood capillaries.