Effects of glucagon and insulin on poly(ADP-ribose) polymerase activity and blood ketone body ratio after partial hepatectomy in rats

The effects of glucagon and insulin on liver nuclear poly(ADP-ribose) polymerase activity and blood ketone body ratio after rat partial (68%) hepatectomy were examined. Liver weight regeneration rate was enhanced by glucagon and insulin after 5th posthepatectomy day. The maximal value of poly(ADP-ribose) polymerase activity without glucagon and insulin was revealed as 368 +/- 64 pmole/mg/min on 5 days after the hepatectomy. In contrast, the enzyme activity with glucagon and insulin reached to the peak value as 253 +/- 42 pmole/mg/min on 2 days after the hepatectomy. The amounts of DNA per nuclear protein showed similar changes with the changes of poly (ADP-ribose) polymerase activity after the hepatectomy. Blood ketone body ratio showed almost similar changes in both groups, except transitional decrease in the group without glucagon and insulin on 5th postoperative day. It is suggested that, to promote remnant liver regeneration, the combined therapy of glucagon and insulin may act directly to nucleic acid metabolism through the changes of poly(ADP-ribose) polymerase activity and preserve energy charge level by the suppression of NAD consumption by massive poly(ADP-ribose) formation.