Changes in lipid parameters after intestinal resection or bypass in the rat.

Intestinal resection, bypass and adaptative postoperative mechanisms developed as a consequence of that surgery, are considered good methods for improving knowledge of gastrointestinal physiology as well as possible effects that the intestine could have on the general metabolism. 50% jejunoileal bypass (BP), 50% proximal (PR) and distal (DR) intestinal resections were performed on rats to compare the influence of resected intestinal segments or bypassed loop localization could exert on different serum lipid parameters. One month after surgery significant increases in total serum cholesterol and cholesterol esters were found. There was no change in free cholesterol. A decrease in triglyceride was observed after distal and proximal resection but no changes after bypass. The cholesterol/phospholipid ratio was increased after resection and after bypass. It has been suggested that the changes in lipid metabolism produced after resections and bypass depend mainly on the loss of absorptive surface rather than on the position of the resected segment. The bypass loop may itself still exert some influence on lipoprotein metabolism, mainly on high density lipoprotein-cholesterol.