Effect of total exclusion of the exocrine pancreas in the rat upon in vitro esterification of C14-labeled cholesterol by the intestine and upon lymphatic absorption of C14-labeled cholesterol

Abstract

The esterification of free cholesterol-4-C14 by extracts of acetone powders prepared from the small intestines was measured in normal rats and in rats in which all of the pancreas, except for a small portion along the splenic vessels, was removed. The acinar cells of the pancreatic remnant degenerated, thus providing a nondiabetic rat containing no functioning exocrine pancreatic tissue. Depriving the rat of its external secretions of the pancreas in this manner resulted in a reduction—but not in complete loss—of the intestine's capacity to esterify free cholesterol. The absorption of tube-fed cholesterol-4-C14 into thoracic duct lymph of the rats totally deprived of functioning exocrine pancreatic tissue was depressed, but the proportion of sterol-C14 recovered in the esterified form in the thoracic duct lymph of the operated rats was normal. It is concluded that an enzyme capable of esterifying free cholesterol, not derived from the pancreas, is present in the small intestines of the rat, The fact that the pancreatic juice enzyme that esterifies cholesterol was absent from the intestines of our operated rats could account for the reduction in esterification of the sterol and in its absorption. However, other mechanisms that could just as well explain these observations have also been considered.