Serum Insulin in Type I Glycogenosis: Effect of Galactose or Fructose Administration

Upon infusion of galactose, two patients with glucose-6-phosphatase deficiency did not respond with a rise in serum insulin while glucose elicited such a response. Similarly, infusion of fructose was followed by an increase in serum insulin, although no glucose was produced because of the glucose-6-phosphatase deficiency. Since fructose administered to patients with fructose intolerance does not have such an insulin releasing effect, it is speculated that an intermediary metabolite rather than fructose itself triggers the secretion of insulin.