Has the arginase inhibitory role in liver cell multiplication in vivo?

Abstract

An increase of arginase activity was found in the liver 6 and 12 hrs after partial hepatectomy in saline-treated (11.9 and 20.3%, respectively) and in phenobarbital-treated animals (16.3 and 61.8%, respectively). In both groups the increase of arginase activity was achieved only after the removal of a "threshold" amount of liver tissue. For saline-treated rats the "threshold" amount was two thirds hepatectomy and in phenobarbital treated rats 34% hepatectomy. In both groups of animals the maximal response was obtained at two thirds hepatectomy, which at the same time provokes the maximal proliferative activation of the liver cells. The existence of a positive correlation between the degree of increase of arginase activity during the first hours after partial hepatectomy and the degree of DNA synthesis and mitotic activiation of liver tissue, which followed 12 hrs later, excludes the arginase as a factor which inhibits cells multiplication during the regenerative growth of the liver. © 1972 Springer-Verlag.