title: Hepatic redox state and gluconeogenesis from lactate in vivo in the rat.
abstract: 1. To examine the role of the hepatic redox state on the rate of gluconeogenesis the effects of sodium crotonate injection (6mmol/kg body wt.) on rat liver metabolite concentrations and gluconeogenesis from lactate were studied in vivo. 2. Crotonate caused a marked oxidation of cytoplasmic and mitochondrial redox couples; decreases were observed in the ratios of [lactate]/[pyruvate], [glycerol 3-phosphate]/[dihydroxyacetone phosphate], [hydroxybutyrate]/[acetoacetate] and measured [NAD(+)]/[NADH]. 3. Increases occurred in the liver concentrations of all gluconeogenic intermediates from pyruvate through to glucose 6-phosphate, but there was no change in lactate concentration. 4. To determine whether gluconeogenesis from lactate was altered by the more-oxidized hepatic redox state l-[2-(14)C]lactic acid was infused into the inferior vena cava (50mumol/min per kg body wt.) and the incorporation of radioactivity into blood glucose was measured. 5. Administration of crotonate transiently decreased the rate of lactate incorporation into glucose but within a few minutes the rate of incorporation returned to that of the controls. 6. The results indicate that in these experiments alteration of the NAD(+)-NADH systems of cytoplasm and mitochondria to a more-oxidized state did not change the rate of gluconeogenesis.
mesh_terms: D000090:Acetoacetates / Q000378:metabolism; D000096:Acetone / Q000378:metabolism; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002247:Carbon Isotopes; D002852:Chromatography, Ion Exchange; D002854:Chromatography, Paper; D003437:Crotonates / Q000494:pharmacology; D005943:Gluconeogenesis; D005947:Glucose / Q000378:metabolism; D005994:Glycerophosphates / Q000378:metabolism; D006885:Hydroxybutyrates / Q000378:metabolism; D007700:Kinetics; D007773:Lactates / Q000378:metabolism*; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009243:NAD / Q000378:metabolism; D009943:Organophosphorus Compounds / Q000378:metabolism; D010084:Oxidation-Reduction; D011773:Pyruvates / Q000378:metabolism; D051381:Rats; D013217:Starvation; D013997:Time Factors; D014306:Trioses / Q000378:metabolism
chemical_list: D000090:Acetoacetates; D001786:Blood Glucose; D002247:Carbon Isotopes; D003437:Crotonates; D005994:Glycerophosphates; D006885:Hydroxybutyrates; D007773:Lactates; D009943:Organophosphorus Compounds; D011773:Pyruvates; D014306:Trioses; D009243:NAD; D000096:Acetone; D005947:Glucose