Surgical sterilization by vasectomy and its effects on the structure and function of the testis in man.

The early and late effects of vasectomy have been investigated in 40 men. Besides histopathological examination, the volume of the testis and its total content of testosterone-screting Leydig cells have been measured. The volume of the testis showed a wide normal variation (5-3-23-3 ml) but was not significantly changed by vasectomy. One month after vasectomy widespread degeneration of the germinal epithelium, thickening of the basement membrane and some intertubular fibrosis were observed. Spermatogenesis had ceased. However, cases examined 2-31/2 years later showed an essentially normal structure with active spermatogenesis. This indicates that regeneration does occur spontaneously, even without recanalization. Whether the sperms formed are functionally normal remains uncertain. The normal total Leydig cell volume was 2-2 plus or minus 0-4 ml/testis in young adults and showed a modest increase after vasectomy, rising to 2-5 plus or minus 0-5 ml after 1 month and 2-6 plus or minus 0-5 ml after 2-31/2 years. The findings have been discussed in the light of Steinach's (1927) original hypothesis that vasectomy can rejuvenate ageing males by improving the endocrine function of the testis.