Leg and splanchnic arteriovenous differences of plasma citrate in exercising man.
Arteriovenous concentration differences of plasma citrate, glucose, lactate, pyruvate, free fatty acids, acetoacetate, and 3-hydroxybutyrate were determined across the leg and the splanchnic vascular bed in six healthy subjects in postabsorptive state, during 30 min of exercise (60--70% work load) and 65 min of recovery. A release of citrate across the leg and an uptake across the splanchnic vascular bed were found. Citrate arterial-femoral venous difference at rest, -19 +/- 2 mumol/l was abolished after 5 min of exercise and rebuilt during continuous work to reach peak value, -30 +/- 3 mumol/l at 20 min recovery. During exercise increasing negative arterial-femoral venous citrate differences were inversely related to fractional glucose extraction across the leg. Arterial-hepatic venous citrate difference at rest, 10 +/- 2 mumol/l, increased twofold during recovery. The results agree with the concept that a citrate inhibition of phosphofructokinase may be of regulatory importance for muscular glycolysis and glucose uptake as well as for hepatic glycolysis and gluconeogenesis in man during exercise.
D000328:Adult; D002951:Citrates / Q000097:blood*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D005263:Femoral Artery; D005268:Femoral Vein; D006503:Hepatic Veins; D006801:Humans; D007657:Ketone Bodies / Q000097:blood; D007773:Lactates / Q000097:blood; D007866:Leg / Q000098:blood supply; D008297:Male; D010732:Phosphofructokinase-1 / Q000378:metabolism; D005082:Physical Exertion; D011773:Pyruvates / Q000097:blood; D013997:Time Factors
D002951:Citrates; D005230:Fatty Acids, Nonesterified; D007657:Ketone Bodies; D007773:Lactates; D011773:Pyruvates; D010732:Phosphofructokinase-1