Alteration in sympathetic nerve activity during liver regeneration in rats after partial hepatectomy

To determine if the sympathetic nerve has a role in liver regeneration, the alterations of tissue norepinephrine (NE) content and its turnover were measured in rats after partial hepatectomy. NE content per unit liver mass decreased progressively to about one-fourth of controls by the ninth day after partial hepatectomy. Since the total amount of NE in the whole liver did not change during nine days of liver regeneration, it was supposed that sympathetic innervation could make slower progress than proliferation of hepatocytes. Fractional turnover rate of NE was reduced transiently in regenerating liver 24-48 h after partial hepatectomy and recovered to normal 8-9 days after the operation. Such a transient reduction of NE turnover was observed specifically in the liver. These results suggest that sympathetic nerve activity of the liver is suppressed at the early stage of regeneration.