Rare Sugar Syrup Containing d-Allulose but Not High-Fructose Corn Syrup Maintains Glucose Tolerance and Insulin Sensitivity Partly via Hepatic Glucokinase Translocation in Wistar Rats

Abstract

Ingestion of high-fructose corn syrup (HFCS) is associated with the risk of both diabetes and obesity. Rare sugar syrup (RSS) has been developed by alkaline isomerization of HFCS and has anti-obesity and anti-diabetic effects. However, the influence of RSS on glucose metabolism has not been explored. We investigated whether long-term administration of RSS maintains glucose tolerance and whether the underlying mechanism involves hepatic glucokinase translocation. Wistar rats were administered water, RSS, or HFCS in drinking water for 10 weeks and then evaluated for glucose tolerance, insulin tolerance, liver glycogen content, and subcellular distribution of liver glucokinase. RSS significantly suppressed body weight gain and abdominal fat mass (p < 0.05). The glucose tolerance test revealed significantly higher blood glucose levels in the HFCS group compared to the water group, whereas the RSS group had significantly lower blood glucose levels from 90 to 180 min (p < 0.05). At 30, 60, and 90 min, the levels of insulin in the RSS group were significantly lower than those in the water group (p < 0.05). The amount of hepatic glycogen was more than 3 times higher in the RSS group than that in the other groups. After glucose loading, the nuclear export of glucokinase was significantly increased in the RSS group compared to the water group. These results imply that RSS maintains glucose tolerance and insulin sensitivity, at least partly, by enhancing nuclear export of hepatic glucokinase.

Tracing the Anti‐Inflammatory Mechanism/Triggers of d‐Allulose: A Profile Study of Microbiome Composition and mRNA Expression in Diet‐Induced Obese Mice

“…However, the underlying molecular mechanisms for chronic inflammation caused by obesity remain unclear. In a previous study, d ‐allulose improved diet‐induced obesity through the regulation of mRNA expression in the small intestine, liver, and eWAT . This study elucidated the molecular mechanisms of metabolic regulation in response to d ‐allulose supplementation in diet‐induced obese C57BL/6J mice under pair‐fed conditions, based on mRNA‐seq and microbiome transcriptomic analysis.…”

The effect of small doses of fructose and allulose on postprandial glucose metabolism in type 2 diabetes: A double‐blind, randomized, controlled, acute feeding, equivalence trial

“…This enables the liberated and activated glucokinase to translocate from the nucleus to the cytosol, where it can drive hepatic glucose uptake, promote glycogen synthesis, suppress hepatic glucose output and reduce plasma glucose levels 40. In support of this hypothesis, immunohistochemical analyses in allulose‐fed rats have shown induction of glucokinase translocation from the nucleus to the cytoplasm and an increased amount of hepatic glycogen content after glucose loading 22, 44. No studies have been conducted in humans to confirm this mechanism.…”

“…40 In support of this hypothesis, immunohistochemical analyses in allulose-fed rats have shown induction of glucokinase translocation from the nucleus to the cytoplasm and an increased amount of hepatic glycogen content after glucose loading. 22,44 No studies have been conducted in humans to confirm this mechanism.…”

Food Industrial Production of Monosaccharides Using Microbial, Enzymatic, and Chemical Methods

“…This sugar has been discussed in so many reports by Izumori [49][50][51]. D-Allulose-containing sugar syrup is produced from high Fru corn syrup at an industrial scale by an alkaline isomerization method [19,20]. Moreover, in a study using the immobilized enzyme column reaction method, the total D-allulose production yield was 215 kg/L immobilized enzyme, which is the highest reported enzyme yield to date [21].…”