Abstract
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.