The effect of portacaval shunt (PCS) with and without hepatic arterialization (HA) upon the liver morphology, hemodynamics, and in relation to testicular weight, histology, and plasma sex steroid levels has been investigated in male rats. PCS rats showed a significant decrease in hepatic blood flow, body and liver weights, together with signs of severe hypogonadism. In contrast, in HA rats the increment in liver blood flow was associated with higher body and liver weights. In spite of total portal blood shunting, a beneficial effect on testicular morphology and an increase in plasma testosterone level were observed. In respect to plasma estradiol levels the intergroup differences could not be evaluated due to large individual variations. This was probably caused by the presence of cross-reactive plasma component(s) masking the level of endogenous estrogen. It is concluded that portosystemic shunting is not of primary importance in the etiology of PCS-related hypogonadism in the male.