Gluconeogenic response to mannoheptulose in the rat.

Since administration of mannoheptulose induces temporary hyperglycemia, the present study was conducted to elucidate this phenomenon. The results indicate that mannoheptulose stimulates the activity of hepatic fructose-1,6-diphosphatase and phosphoenolpyruvate carboxykinase, and enhances incorporation of alanine into blood glucose and hepatic glycogen. In addition, mannoheptulose increases plasma levels of glucagon and hepatic cyclic AMP concentration. Gluconeogenic effects of mannoheptulose appear to be mediated by glucagon.