POSTPRANDIAL LIPID AND HORMONE RESPONSES TO MEALS OF VARYING FAT CONTENTS - MODULATORY ROLE OF LIPOPROTEIN-LIPASE

Objective: Substrate and hormone responses to meals of differing fat c ontent were evaluated in normal subjects in order to investigate mecha nisms underlying the regulation of postprandial lipoprotein concentrat ion. Design: A randomised cross-over study with three different meals on three occasions. Setting: Free-living subjects associated with Surr ey University. Subjects: Ten male volunteers (aged 18-23 years) were r ecruited. Interventions: Three test meals containing 20, 40 or 80g fat but identical carbohydrate and protein content were randomly allocate d to volunteers. Major outcome measures: Pre- and postprandial blood s amples were taken for the analysis of plasma triacylglycerol, non-este rified fatty acids, glucose, immunoreactive insulin and glucose-depend ent insulinotrophic polypeptide levels and postheparin lipoprotein lip ase activity measurements. Results: Peak triacylglycerol concentration s and lipoprotein lipase activity measurements were significantly high er following the 80 g than the 20 g fat meal (P = 0.009 and P = 0.049 respectively). Areas under the glucose-dependent insulinotrophic polyp eptide time-response concentration curves were significantly higher fo llowing the 80 g compared with the 20 g fat meal (P = 0.04), but no di fferences in insulin response to the meals were seen. The 30-360 min d ecrease in the non-esterified fatty acid concentration was less follow ing the 80g than the 20 g meal (P 0.001). Conclusions: The results sug gest that glucose-dependent insulinotrophic polypeptide may mediate in creased lipoprotein lipase activity in response to fat-containing meal s and may play a role in circulating lipoprotein homeostasis. This mec hanism may be overloaded with high fat meals with adverse consequences on circulating triacylglycerol and NEFA concentrations. Sponsorship: This work was funded by the Agricultural and Food Research Council. De scriptors: blood lipids, chylomicron, postprandial, triglyceride.