Quantitative study of spermatogenesis in vasectomized mice.

Adult mice were vasectomized under semi-sterile conditions and examined five weeks later. The weight of the epididymis was increased but none of the animals had developed spermatic granulomas. The concentration of testosterone in the plasma, the body weight and the weight of the testes were not affected by vasectomy. Cross sections of the testes were prepared for histological examination and the nuclei of the various types of germinal cells were enumerated at stage VII of spermatogenesis. Vasectomy caused a small, but statistically significant, decrease in the number of preleptotene spermatocytes, pachytene spermatocytes and step 7 spermatids.