Comparison of dietary triacylglycerol oil and diacylglycerol oil in protein kinase C activation

Abstract

The objective of the present study was to compare the effects of dietary diacylglycerol (DAG) oil with triacylglycerol (TAG) oil with a similar fatty acid composition (fatty acid chain range: C14–C22, C18 fatty acid chain: >90%) on protein kinase C (PKC) activation and on 1,2-DAG levels. Using male Wistar rats, no differences in cytosolic and membrane PKC activities in the lingual, esophageal, gastric, small intestinal, cecal, proximal colonic, and distal colonic mucosa were found between the 5% DAG and TAG oil groups, or between the 23% DAG and TAG oil groups after 1 month of feeding. The 1,2-DAG levels in the cecum and colon contents and in the feces and serum in male Wistar rats after a diet containing either 10% DAG or TAG oil feeding were similar between the groups. Moreover, exposure of Caco-2 cells to DAG and TAG oils had no effect on PKC activity in the membrane fraction, but 1,2-dioctanoyl glycerol composed of short-chain fatty acids (C8) did, suggesting the absence of an influence on PKC activity in DAG and TAG oils composed of long-chain fatty acids. In summary, the effects of DAG oil ingestion on PKC activity in the digestive tract and lingual mucosa, and on 1,2-DAG levels in the cecum and colon contents and in the feces and serum were similar to those observed for TAG oil ingestion.