Stimulated rat liver mitochondrial biogenesis after partial hepatectomy

In order to elucidate the response of mitochondria to the increase in cellular energy demand after hepatectomy, we have examined the effects of partial hepatectomy and hepatic artery ligation on the energy-transducing system of rat liver mitochondria. Specific content of DNA in the mitochondria increased on the first day after the hepatectomy and reached 150% of the original value. Oxidative phosphorylation capacity of the mitochondria started to increase on the first postoperative day. In contrast, specific enzymic activities, specific cytochrome contents, and subunit contents of the energy-transducing complexes in the isolated mitochondria were significantly increased only from the second postoperative day. The ligation of the hepatic artery did not inhibit the amplification of the mitochondrial function. The immunostain for ubiquinol-cytochrome c oxidoreductase was increased predominantly in the portal area of the hepatic lobules of the hepatectomized rats. These results suggest that enhancement of the mitochondrial oxidative phosphorylation system after hepatectomy is based on the increase of the amount of the complexes in the inner membrane, which is closely related to replication of mitochondrial DNA, and that the blood supply from the hepatic artery is not an important factor in the mitochondrial amplification in rats.