Bacterial peritonitis with hyperamylasemia in the absence of ultrastructural changes of pancreas. A light and electron microscopic study in the rat.

Bacterial peritonitis was induced in rats by injecting two concentrations of E. coli (10(6) cfu/mL or 10(8) cfu/mL) and B. fragilis (10(8) cfu/mL or 5 x 10(8) cfu/mL) ip. Twenty-four hours later the serum amylase activity was significantly increased in both groups. At light microscopy scattered polymorphonuclear leukocytes were observed in the pancreatic glands of both controls and rats receiving bacteria. In the peripancreatic fat microabscesses were seen in 5 of 10 animals receiving the higher dose of bacteria. There were no fat necroses. Morphometric analysis of the pancreatic ultrastructure revealed a marginal but statistically nonsignificant increase of the volume density of connective tissue stroma indicating slight edema. There were no apparent changes seen within the acinar cells. Morphometrically the granule volume density, numerical density of granule profiles, numerical granule density, nuclear volume density, and numerical condensing vacuole density were similar between controls and animals receiving bacteria. We conclude that, although bacterial peritonitis caused hyperamylasemia, no obvious morphologic damage was found in the exocrine pancreas.