In previous studies of liver regeneration following partial hepatectomy (PH) in rats, we noted a decrease in serum amylase activity. The present study was carried out to determine if the decrease in serum amylase following PH corresponds to a decrease in pancreatic parenchymal exocrine enzyme activity. Male Wistar rats (275 g) underwent either 60% PH or sham laparotomy (SL). A third group, serving as controls (CON), received no surgical procedure. All groups were pair-fed a nutritionally balanced diet. After 48 hr, pancreas, blood, and liver were removed for analysis. Results showed that PH decreased pancreatic parenchymal protein by 43%, lipase by 44%, and trypsin by 22% compared to controls. Serum amylase decreased by 28%, a finding similar to previous experiments. However, pancreatic parenchymal amylase activity was not affected. It remains to be determined whether the reduced pancreatic function affects digestion and absorption. © 1988.