Are leukocytes involved in the human chorionic gonadotropin-induced increase in testicular vascular permeability?

Adult male rats were given a single sc injection of human CG (hCG). The volume density of polymorphonuclear leukocytes (PMNs) located in blood vessels or in the interstitial space was determined by morphometry. The volume of testicular interstitial fluid (IF) was also measured. hCG in doses from 50-800 IU increased the IF volume 8 h after treatment and resulted in migration of PMN into the interstitial space. In contrast, treatment with 12.5 IU hCG, although increasing intratesticular testosterone to about 50% of the maximal value, did not increase the volume of IF, and no leukocytes appeared in the interstitial space. Treatment with 50 IU hCG sc increased the volume of IF at 8, 16, and 32 h after treatment. The increase in IF volume, which is a reliable estimator of changes in the vascular permeability, was preceded by an intravascular accumulation of PMNs. Four hours after hCG treatment, there was a 6-fold increase in the volume density of intravascular PMNs. Later, leukocytes migrated into the interstitial space reaching a maximal concentration 8 h after hCG treatment (at that time 6.4 +/- 0.7 X 10(-5) of the total testis volume was composed of leukocytes). The number of interstitial PMNs declined thereafter and by 32 h they were no longer observed. It is suggested that leukocytes could be involved in mediating the hCG-induced increase in vascular permeability in the testis.