Intratubular hydrostatic pressure in testis and epididymis before and after long term vasectomy in the guinea pig

Abstract

Intratubular hydrostatic pressure was measured in vivo in the testis, caput epididymidis, and cauda epididymidis of the guinea pig before and after vasectomy. Pressures in these locations ranged from 2 to 11 cm H2O in the normal animals. The mean pressure in the caput epididymidis was significantly greater (P<0.005) than the mean pressures in the seminiferous tubules and the proximal cauda. The mean pressure was greater (P<0.005) in the distal cauda than in the proximal cauda. In light of the present results, and of similar findings in the golden hamster reported previously, the possible mechanisms for the transport of sperm and fluid through the male reproductive tract are examined. The hydrostatic pressure in the distal cauda epididymidis both at 4 mth and 1 yr after vasectomy in the guinea pig was significantly greater (P<0.001) than normal, and reflects the accumulation of sperm and fluid. However, the pressures in the caput epididymidis and proximal caudal tubules were not significantly elevated. Thus, changes in spermatogenesis observed after long term vasectomy in the guinea pig are not the result of the direct transmission of the increased caudal pressure to the testis.