To determine whether the metabolism of diet-derived
triglycerides (TG) is acutely regulated by the consumption of insulinogenic
carbohydrates, we measured the effects of
glucose ingestion on oral and intravenous fat tolerance, and on serum
triglyceride concentrations obtained during duodenal fat perfusion. Postprandial
lipemia was diminished by the ingestion of 50 g (148 +/- 121 mg.dl-1 x 7 h-1 vs 192 +/- 124 mg.dl-1 x 7 h-1, P less than 0.05) and 100 g (104 +/- 106 mg.dl-1 x 7 h-1 vs 171 +/- 104 mg.dl-1 x 7 h-1, P less than 0.05)
glucose. Peak postprandial TG concentrations occurred later after meals containing
glucose and fat than after meals containing fat alone. This effect could be reproduced when an iso-osmotic quantity of
urea was substituted for
glucose in the test meal.
Starch ingestion had no discernible effect on postprandial
lipemia. Intravenous fat tolerance was similar before (4.9 +/- 1.2%.min-1) and 2 h (4.4 +/- 1.3%.min-1) and 4 h (4.8 +/- 1.5%.min-1) after 50 g
glucose ingestion. During duodenal fat perfusion,
glucose ingestion caused a progressive decrease in plasma
triglyceride concentrations. These data suggest that
glucose ingestion diminishes postprandial
lipemia in a dose-dependent manner, but that this effect is not due to increased clearance of
triglyceride from the circulation. The hypotriglyceridemic effects of
glucose appear to reflect delayed gastric emptying and decreased hepatic secretion of
triglyceride.