Nitric oxide synthase activity in arterial tissues of cirrhotic rats.

The changes in the activities of constitutive nitric oxide (NO) synthase (cNOS) and inducible NOS (iNOS) were investigated in arterial tissues of CCl4-induced cirrhotic adult SD rats. The aortic tissue homogenate were prepared in normal and cirrhotic rats. NOS activity was measured by conversion of 3H-arginine to 3 H-citrulline. The activities of cNOS and iNOS were calculated in terms of presence or absence of Ca2+. The results showed that activities of total NOS, cNOS and iNOS in arterial tissues were all increased significantly in cirrhotic rats as compared with those in normal controls. There was a significant positive correlation between the activities of total NOS and cGMP content in cirrhotic arterial tissues.