Fructose administration stimulates glucose phosphorylation in the livers of anesthetized rats.
A method allowing one to measure the rate of glucose phosphorylation in the livers of anesthetized rats is described. Upon injection of [2-3H]glucose into the portal vein, about 90% of the radioactivity remained in the liver for approximately 30 s. The proportion of radioactivity accounted for by tritiated water increased linearly at a rate of about 5%/min in control animals. Fructose injected into the penile vein stimulated this rate up to 2.2- and 2.7-fold in fed and overnight starved rats respectively, a maximal effect being observed at a dose of 50 mg/kg under both conditions. Fructose was also active when administered by intragastric infusion. The ketose caused increases in the concentration of fructose 1-phosphate, which reached values known to relieve the inhibition exerted on glucokinase by its regulatory protein.
Van Schaftingen
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Laboratory of Physiological Chemistry, International Institute of Cellular and Molecular Pathology, Brussels, Belgium.
Davies
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DR
D000758:Anesthesia; D000818:Animals; D005632:Fructose / Q000494:pharmacology*; D005941:Glucokinase / Q000032:analysis; D005947:Glucose / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D008297:Male; D010766:Phosphorylation; D051381:Rats; D011919:Rats, Inbred Strains
D005632:Fructose; D005941:Glucokinase; D005947:Glucose