Leucocytes mediate the hCG-induced increase in testicular venular permeability

Human chorionic gonadotrophin (hCG) treatment of adult male rats induces microvascular changes in the testis consisting of abolished vasomotion, an accumulation of leucocytes in postcapillary venules and increased vascular permeability. To study the role of leucocytes, rats were made leucopenic with a specific antineutrophil serum (ANS). Testicular interstitial fluid volume was decreased in leucopenic rats. Leucopenic rats also failed to show an hCG-induced increase in venular permeability as in saline-treated rats. The normally pulsatile blood flow pattern (vasomotion) persisted in leucopenic rats but was abolished after hCG treatment both in saline-treated and leucopenic rats. Plasma testosterone concentration after hCG treatment was not affected by elimination of circulating polymorphonuclear (PMN) leucocytes. It is concluded that PMN leucocytes mediate in part the hCG-induced increase in testicular venular permeability but not the hCG-induced inhibition of vasomotion.