Increase of phosphatidylethanolamine N-methyltransferase activity in the small bowel brush-border membrane after massive intestinal distal resection in rats.

Phosphatidylcholine plays an important role for the structure and function of the cell membrane, and its synthesis from phosphatidylethanolamine is catalyzed by phosphatidylethanolamine N-methyltransferase (PEMT). This study investigates changes in PEMT activity in the intestinal brush border membrane after extensive distal enterectomy (60%) in 40 Wistar rats. Four groups, each of 10 rats, were killed immediately after surgery (day 0) and on the 7th, 14th and 28th day postoperatively. Samples from jejunum were collected for histomorphometry and PEMT activity was determined by measuring the incorporation of [(3)H]-methyl groups from S-adenosyl-L-(methyl-(3)H)-methionine into phospholipids. Enterectomy induced 30%, 48% and 21% increases in the jejunum villus cell population, and 32%, 81%, and 32% in the crypt cell population at postoperative days 7, 14, and 28, respectively. PEMT activity increased 41% at day 14, suggesting functional differentiation, remaining at this level until day 28, when a reduction in the epithelial cell population was observed, thus indicating that adaptation was completed. The observed increase in PEMT-specific activity in the residual intestine suggests that extensive enterectomy stimulates the synthesis of phosphatidylcholine by the PEMT-controlled pathway.