Protein Carboxylmethylase and Germ Cell Adenylyl Cyclase at Specific Stages of the Spermatogenic Cycle of the Rat

Abstract

The activities of two testicular enzymes, protein carboxylmethylase (PCM) and Mn²⁺-dependent adenylyl cyclase (AC), both of which have been shown to be primarily localized in haploid germ cells, were assessed at various stages of the spermatogenic cycle in the rat. The two enzymes displayed the lowest specific activity at stages VII and VIII of the cycle. A gradual increase in the activity of both enzymes was observed from stages XII to IV–V with maximal levels at stages II–III. During the study a highly positive correlation (r = 0.91, P<0.001) was seen between PCM and AC activities. These results show a close parallelism and a stage-dependent variation of PCM and AC activities during the seminiferous epithelial cycle in the rat.