The properties and distribution of an enzyme in the epididymis of the mouse hydrolyzing thiamine pyrophosphate were investigated using cytochemical and quantitative methods. Cytochemical study indicated thiamine pyrophosphatase to be restricted to the Golgi regions of the epithelial cells lining the epididymal canal. Activity due to this enzyme was easily separated from that due to alkaline phosphatase (which also hydrolyzed thiamine pyrophosphate) on the basis of differences in localization and on the greater sensitivity of the latter enzyme to cysteine. The thiamine pyrophosphatase present in the epididymis of the mouse had optimal activity in the region of pH 9.5. In the acid range, activity was greatly restricted but the distribution pattern did not differ from that observed in the alkaline range nor did it resemble the pattern of activity associated with acid phosphatase activity in this tissue. Quantitative determinations supported the cytochemical investigations in terms of a pH optimum in the alkaline range and the resistance of thiamine pyrophosphatase to cysteine inhibition.
The properties of diphosphopyridine nucleotide diaphorase and the lactic dehydrogenase-diphosphopyridine nucleotide diaphorase system in the epididymis of the mouse have been investigated by cytochemical and quantitative methods. In normal mice diphosphopyridine nucleotide diaphorase activity was homogeneously distributed within the cytoplasm of the epithelial cells of the epididymal canal. A gradient of activity existed along the duct, with the lowest levels of activity appearing in the head segments and the highest levels in the body and tail segments. The lactic dehydrogenase-diphosphopyridine nucleotide diaphorase system differed in its cytological distribution from diphosphopyridine nucleotide diaphorase. In the cells of the body portion of the epididymal canal this system showed high levels of activity in the cell apex with low levels of activity prevailing in the general cytoplasm. In other areas the system showed low levels of activity homogeneously distributed throughout the cytoplasm. Cytochemical studies indicated that the activity of diphosphopyridine nucleotide diaphorase was depressed by orchidectomy and restored by testosterone propionate administration. The activity of this enzyme was unaffected by section of the vasa efferentia (vasectomy). The activity of the lactic dehydrogenase-diphosphopyridine nucleotide diaphorase system was depressed by vasectomy and orchidectomy. Testosterone propionate restored activity of tissues from castrated animals to levels prevailing in vasectomized animals but did not re-establish the distribution pattern observed in normal animals. Quantitative determinations confirmed and extended cytochemical observations.
TEN P'IGURESChemical and histochemical studies have demonstrated a striking complexity of organization in the epididymal canal of the mouse (Allen and Slater, '57). Alkaline phosphatase arid aliesterase were present in significantly different amounts (or activities) in the head, and body and tail of the epididymis. Marked lobal variation was observed in the activities of these enzymes in the head segments of the epididymal duct. Nonciliated, club-shaped cells, enzymatically distinct from other cells were demonstrated in head lobe 3. These results appeared to warrant investigation of other enzymes in this tissue. The present paper deals with the behavior of chemically and histochemically determined acid phosphatase in the epididymis of intact, castrate and hormone replaced castrate mice.
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