Ultrastructural localisation of alkaline phosphatase in the testis of domestic fowl.

The ultrastructural distribution of alkaline phosphatase has been investigated in the testis of the domestic fowl. Enzyme activity was observed in the germinal epithelium and in the peritubular tissue. In both situations the activity was located in the plasma membranes. The activity in the germinal epithelium was marked basally in the germinal cells and in the Sertoli cells. There was a gradual reduction and an ultimate disappearance of enzyme activity towards the luminal region. The presence of enzyme in the germinal epithelium is in contrast to results of similar studies in some mammals. The peritubular localisation is comparable to that of mammals and confirms light microscope observations reported for the fowl testis.