Mutarotase and glucose anomers

Effects of D-glucose anomers on sweetness taste and insulin release in man

Insulin release was examined in human subjects after lingual applications of D-glucose and its anomers. A dose-dependent increase in the insulin release was noted following the application of equilibrated D-glucose consisting of 36% alpha- and 64% beta-anomer. The response was not reproduced after administration of atropine. The magnitude of insulin release produced by alpha-anomer was different from that induced by beta-anomer in men who could not differentiate between sweetness of the two anomers. Results indicate that recognition of sweetness in the cortex is unrelated to the insulin response, and suggest that a subcortical mechanism may detect qualitative differences in taste and produce the oral phase of insulin secretion via vagus action in humans.

Effects of D-glucose anomers on sweetness, taste and gastric acid secretion in man

Gastric acid outputs were examined in human subjects after lingual applications of d-glucose and its anomers. A dose-dependent increase in the acid output was noted following the application of equilibrated D-glucose consisting of 36% alpha- and 64% beta-anomer. The response was not reproduced after administration of atropin. The magnitude of acid output produced by alpha-anomer was different from that induced by beta-anomer in men who could not differentiate between sweetness of the two anomers. Results indicate that recognition of sweetness in the cortex is unrelated to the gastric response, and suggest that a subcortical mechanism may detect qualitative differences in taste and produce the oral phase of gastric acid secretion via vagus action in humans.

Different effects of D-glucose anomers on enhanced secretion of gastric acid in rat

The injection of alpha-, beta-, or equilibrated (alpha: 36%, beta: 64%) D-glucose solution into the cranial side of the carotid artery decreased gastric acid output caused by insulin in rats with bilateral adrenalectomy. This effect was not reproduced after vagotomy at the cervical level. Of the 3 forms of D-glucose solution the effect of beta-D-glucose was greatest. The injection of isotonic NaCl solution, however, produced no change in acid output. These results suggest that blood beta-D-glucose may play a predominant role in activating a brain mechanism which controls gastric acid secretion via the vagus nerve.

Inhibition of gastric acid secretion elicited by D-glucose anomers in man

Acid outputs from the stomach were measured after venous administration of D-glucose and its optical anomers in men with insulin hypoglycemia. A significant decrease in gastric acid output was noted after the administration of 277 mM alpha-D-glucose, 277 mM optically equilibrated D-glucose consisting of 36% alpha-anomer and 64% beta-anomer, or 277 mM beta-D-glucose. The effect of beta-D-glucose was most potent in the three forms of D-glucose. NaCl solution, however, produced no appreciable change in the acid outputs. Our findings suggested that, in humans, beta-D-glucose in the blood may play an important role in the activation of glucose-sensitive mechanisms controlling vagally mediated secretion of gastric acid.

Alterations in gastric acid secretion following hepatic portal injections of D-glucose and its anomers

Changes in acid outputs from the stomach were examined after portal injections of D-glucose and its optical anomers in the bilaterally adrenalectomized rats with insulin hypoglycaemia. Significant decrease in gastric acid outputs was noted after portal injections of alpha-D-glucose, optically equilibrated D-glucose (OEDG) consisting of 36% alpha-anomer and 64% beta-anomer and beta-D-glucose. The effect of beta-D-glucose was most potent in reducing the acid outputs and the inhibitory response was entirely prevented by prior vagotomy at the hepatic level. The injections of isotonic NaCl solution, however, produced no change in the acid outputs. Results suggest that changes in glucose levels in the portal vein may modulate gastric acid secretion through hepatic vagal afferents and gastric vagal efferents and suggest that activation of hepatic glucosensitive mechanisms may be dependent on the anomeric stereospecificity of D-glucose in the blood.

Anomeric compositions of D-glucose in tissues and blood of rat

The anomeric compositions of D-glucose in the liver, kidney, heart, blood and plasma of rat were determined by our methods for the assay of D-glucose anomers and the percentages of the beta-anomer were found to be 61.8, 61.0, 62.4, 62.7 and 62.9, respectively.