Effect of lipase inhibition on gastric emptying of, and the glycemic and incretin responses to, an oil/aqueous drink in type 2 diabetes mellitus

This study examined the effects of the lipase inhibitor, orlistat, on gastric emptying of, and the glycemic and incretin hormone responses to, a drink containing oil and glucose components in patients with type 2 diabetes. Seven patients ( aged 58 +/- 5 yr), managed by diet alone, consumed 60 ml olive oil ( labeled with 20 MBq Tc-99m-V-thiocyanate) and 300 ml water containing 75 g glucose ( labeled with 6 MBq Ga-67-EDTA), on two occasions, with and without 120 mg orlistat, positioned in the left lateral decubitus position with their back against a gamma camera. Venous blood samples, for measurement of blood glucose and plasma insulin, glucagon-like peptide-1 and glucose-dependent insulintropic polypeptide were obtained immediately before, and after, the drink. Gastric emptying of both oil (P < 0.001) and glucose (P < 0.0005) was faster after orlistat compared with control. Postprandial blood glucose (P< 0.001) and plasma insulin ( P < 0.05) were substantially greater after orlistat compared with control. In contrast, plasma glucagon-like peptide-1 ( P< 0.005) and glucose-dependent insulintropic polypeptide ( P < 0.05) were less after orlistat. In conclusion, inhibition of fat digestion, by orlistat, may exacerbate postprandial glycemia, as a result of more rapid gastric emptying and a diminished incretin response.