Intestinal Sweet Taste Receptors Disordered in Diabetes
(HealthDay News) – The expression of intestinal sweet taste receptors (STRs) varies according to glycemic status, and is disordered in type 2 diabetes during hyperglycemia, according to a study published online June 12 in Diabetes.
Richard L. Young, PhD, from the University of Adelaide in Australia, and colleagues examined whether STR expression was acutely regulated by changes in luminal and systemic glucose levels, was disordered in type 2 diabetes, and was linked to glucose absorption. Participants included 14 healthy controls and 13 patients with type 2 diabetes who were studied during euglycemia and hyperglycemia. At baseline and after a 30-minute intraduodenal glucose infusion, endoscopic biopsies were collected from the duodenum. Real-time polymerase chain reaction was used to quantify STR transcripts, and plasma was assayed for 3-O-methyl glucose (3-OMG) concentration.
The researchers found that acute variations in glycemia had no impact on intestinal STR transcript levels at baseline in healthy individuals or in patients with type 2 diabetes. After luminal glucose infusion, G-protein-coupled taste receptor family 1 receptor 2 (T1R2) transcript levels increased in both groups during euglycemia; during hyperglycemia, levels decreased in healthy subjects and increased in those with type 2 diabetes. During acute hyperglycemia, plasma 3-OMG concentrations were significantly higher in patients with type 2 diabetes than controls.
"Intestinal T1R2 expression is reciprocally regulated by luminal glucose in health according to glycemic status, but is disordered in type 2 diabetes during acute hyperglycemia," the authors write. "This defect may enhance glucose absorption in type 2 patients and exacerbate postprandial hyperglycemia."