Ultrastructural localization of acid phosphatase activity in the jejunal absorptive cells of fasted rats.

Ultrastructural localization of acid phosphatase activity was investigated in the jejunal absorptive cells of 21 d fasted rats (about 500 g). The enzyme activity was localized on the membrane of microvilli, the lateral cell membrane, the Golgi complex, the lysosomes and the GERL of Novikoff (a part of the smooth surfaced endoplasmic reticulum located in close proximity to the Golgi saccules) of jejunal absorptive cells. Moreover, the lysosomes of various sizes and shapes with acid phosphatase activity was characteristically encountered in the infranuclear cytoplasm. The lysosomes appeared to be autolysosomes .