Influence of vasectomy on the volume of the non-hyperplastic prostate in men

The influence of vasectomy on the volume of the non-hyperplastic prostate was investigated in 24 men referred consecutively for vasectomy. A comparison of trans-rectal prostatic volume determined ultrasonically before vasectomy and three months post-operatively revealed a highly significant decrease (P less than 0.01) in the volume of the peri-urethral portion of the gland. The volume of the outer zone of the prostate did not change significantly (P greater than 0.1). This may indicate that the prostate is not a functionally homogenous organ. It is postulated that there may be a local influence on the prostate via a hormone transported in the deferent duct and/or the deferential vein.