Histochemistry and cytochemistry of thiamine pyrophosphatase (TPP-ase 3.6.1.) in the rat gastric mucosa.

The paper deals with the histochemical and cytochemical distribution of thiamine pyrophosphatase (TPP-ase 3.6.1.) in the normal rat gastric mucosa using the method of NOVIKOFF and GOLDFISCHER (1961). In light microscopy, activity was demonstrated only in the GOLGI apparatus of the foveolar mucous cells; in the other specialized gastric mucosal cells no activity was established. At electron microscopic level, the reaction product was localized in the membranes of the cisternae of the GOLGI apparatus of foveolar mucous cells, undifferentiated neck cells, parietal cells, chief cells and in endocrine cells. The reaction product was not found in the endoplasmic reticulum of any of the above mentioned types of cells with the exception of parietal cells. The deposits of the reaction product in the cytoplasmic membrane, in the capillary endothelium and on the surface of the plasma membrane of foveolar mucous cells represents the sites of activity of alkaline phosphatase. The examination of the TPP-ase in the gastric mucosa inables us to estimate the activity of the GOLGI apparatus of gastric mucosal cells in the norm and in different pathological conditions connected with its changes.