Trophic effect of protal blood in maintenance cultures of adult rat hepatocytes.

The hepatotrophic effect of portal serum was demonstrated in primary monolayer cultures of adult rat hepatocytes: DNA synthesis in cultures incubated for 4 days with pooled portal serum of fed rats was significantly higher than in cultures with peripheral serum from the same animals. This difference was not observed when portal blood was treated with charcoal or obtained from fasting rats. Portal serum from diabetic rats stimulated DNA synthesis less than portal control serum. The trophic effect of portal serum from normal rats was enhanced after tolbutamide injection. The lost tropic effect of charcoal-treated portal serum was completely restored when insulin was added to reobtain a normal portal immunoreactive insulin concentration. Thus, insulin seems to be the main factor responsible for the hepatotrophic action of portal blood in vitro.