Demonstration of thiamine pyrophosphatase in human germ cells and Sertoli cells, a histochemical study.

The distribution of thiamine pyrophosphatase (TPPase) was studied in the human testicular biopsy tissue with the help of a modified histochemical gel method. The spermatogonia showed a large round strongly positive reaction zone in the supranuclear region. The pachytene spermatocytes exhibited a large semicircular TPPase reaction zone around the nucleus directing towards the lumen. The early round spermatids were characterized by a small, round, and weak supranuclear reaction zone. The elongated late spermatids were devoid of TPPase activity. The Sertoli cells possessed a "streamer" like formation of strong TPPase activity spreading from basal to apical portion.