title: Inhibition of gluconeogenesis and glycogenolysis by 2,5-anhydro-D-mannitol.
abstract: 2,5-Anhydro-D-mannitol (100 to 200 mg/kg) decreased blood glucose by 17 to 58% in fasting mice, rats, streptozotocin-diabetic mice, and genetically diabetic db/db mice. Serum lactate in rats was elevated 56% by 2,5-anhydro-D-mannitol, but this could be prevented by dichloroacetate (200 mg/kg) or thiamin (200 mg/kg). In hepatocytes from fasted rats, 1 mM 2,5-anhydro-D-mannitol inhibited gluconeogenesis from a mixture of alanine, lactate, and pyruvate. It also inhibited glucose production and stimulated lactate formation from glycerol or dihydroxyacetone. Glycogenolysis in hepatocytes from fed rats was markedly inhibited by 1 mM 2,5-anhydro-D-mannitol both in the presence or absence of 1 microM glucagon. 2,5-Anhydro-D-mannitol can be phosphorylated by fructokinase or hexokinase to the 1-phosphate and then by phosphofructokinase to the 1,6-bisphosphate. Rat liver glycogen phosphorylase was inhibited by 2,5-anhydro-D-mannitol 1-phosphate (apparent Ki = 0.66 +/- 0.09 mM) but was little affected by 2,5-anhydro-D-mannitol 1,6-bisphosphate. Rat liver phosphoglucomutase was inhibited by 2,5-anhydro-D-mannitol 1-phosphate (apparent Ki = 2.8 +/- 0.2 mM), whereas 2,5-anhydro-D-mannitol 1,6-bisphosphate served as an alternative activator (apparent K alpha = 7.0 +/- 0.5 microM). Rabbit liver pyruvate kinase was activated by 2,5-anhydro-D-mannitol 1,6-bisphosphate (apparent K alpha = 9.5 +/- 0.9 microM), whereas rabbit liver fructose 1,6-bisphosphatase was inhibited by 2,5-anhydro-D-mannitol 1,6-bisphosphate (apparent Ki = 3.6 +/- 0.3 microM). The phosphate esters of 2,5-anhydro-D-mannitol would, therefore, be expected to inhibit glycogenolysis and gluconeogenesis and stimulate glycolysis in liver.
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D003920:Diabetes Mellitus / Q000378:metabolism; D005943:Gluconeogenesis / Q000187:drug effects*; D007773:Lactates / Q000097:blood; D019344:Lactic Acid; D008099:Liver / Q000201:enzymology; D008112:Liver Glycogen / Q000378:metabolism*; D008297:Male; D008353:Mannitol / Q000031:analogs & derivatives* / Q000494:pharmacology; D008355:Mannitol Phosphates / Q000494:pharmacology; D051379:Mice; D008815:Mice, Inbred Strains; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D001786:Blood Glucose; D007773:Lactates; D008112:Liver Glycogen; D008355:Mannitol Phosphates; D019344:Lactic Acid; D008353:Mannitol; C031765:2,5-anhydromannitol; C040222:2,5-anhydromannitol 1-phosphate; C001900:2,5-anhydro-D-mannitol-1,6-diphosphate