FAILURE OF D-FRUCTOSE TO STIMULATE PROTEIN-BIOSYNTHESIS IN PANCREATIC-ISLETS

Rat pancreatic islets were incubated for 90 min with L-[4-H-3]phenylal anine in either the absence or presence of D-glucose and D-fructose. R elative to basal value, D-glucose (16.7 mM) increased the incorporatio n of the tritiated amino acid into trichloroacetic acid-precipitable m aterial. However, when D-fructose was tested in the 80 to 240 mM conce ntration range, it failed to stimulate islet biosynthetic activity. Si nce D-fructose causes, in the same concentration range, a dose-related stimulation of insulin release, the dissociation between the biosynth etic and secretory responses to D-fructose supports the view that the insulinotropic action of the ketohexose does not entail the same metab olic determinants as those operative in glucose-stimulated islets.