THURSDAY, Aug. 13 (HealthDay News) -- A gut hormone released in response to food lowers glucose levels by triggering signals to the brain and liver, but is ineffective in lowering glucose in rats fed a high-fat diet, according to a study in the Aug. 6 issue of Cell Metabolism.
Using a rat model, Grace W.C. Cheung and colleagues at the University of Toronto investigated the function of the peptide cholecystokinin (CCK), whose release from the duodenum in response to nutrients such as lipids is known to reduce food intake.
The researchers found that an increase in CCK-8, the active form of CCK, in the duodenum lowers glucose production via the gut CCK-A receptor, independent of changes in circulating insulin levels. Further investigation showed that CCK-8 acted through a gut-brain-liver neuronal axis. However, CCK-8 was completely ineffective in lowering glucose in rats fed a high-fat diet for three days.
"These findings reveal a novel role of gut CCK that lowers glucose production through a neuronal network and suggest that intestinal CCK-resistance may contribute to hyperglycemia in response to high-fat feeding," Cheung and colleagues conclude.