Glucose-6-phosphate dehydrogenase activity in somatic and germinal cells of the mouse testis

The activity of G6PD was examined by spectrophotometric and electrophoretic assays in cell fractions from the testes of mice at different ages (5-62 days). (1) The G6PD activity of the cells of the seminiferous tubule was as high or higher than that of the interstitial tissue. (2) The high G6PD activity of the testis of the immature mouse was mainly due to a high specific activity of the Sertoli cells which declined with age. (3) The G6PD activity was more easily lost during culture from the germinal cells than from the interstitial or Sertoli cells. (4) All the cell types of the testis contained G6PD and hexose-6-phosphate dehydrogenase. The functional significance of the high G6PD activity in the Sertoli cells of immature mice is not at present understood.