Ultrastructural localization of acid phosphatase activity in the large intestinal principal cells of postnatal rats.

A study was made of ultrastructural localization of acid phosphatase activity in the large intestinal mucosa of postnatal and adult rats. In rats 1 to 5 days old, phosphatase activity was observed on the microvillous membrane, the lateral cell membrane, the Golgi apparatus, the GERL of Novikoff (1963), the tubulo-vacuolar system, and on the supranuclear vacuole of the principal cells of the cecum and the ascending colon. In 30-day-old adult rats acid phosphatase activity, was noted on the GERL and the lysosomes of the principal cells in the cecum and the ascending colon. In all rats, young and adult, acid phosphatase activity was found only on the lysosomes and the GERL of the principal cells of the descending colon. Therefore, it was concluded that the acid phosphatase-containing tubulo-vacuolar system and the supranuclear vacuole in the surface principal cells of the proximal part of the large intestine of suckling rats may possess a strong phagolysosomal function as well as having an absorption capacity the same as ileal cells of suckling rats (Ono and Satoh 1981).