Alterations of plasma lactate and glucose metabolism in obese children.
Using a double stable isotope infusion method, we quantified plasma glucose and lactate inter-relationships in five recently obese children. Compared with five age-matched controls, obese children had an approximately 50% increase of total body lactate turnover [167 +/- 20 vs. 111 +/- 20 (SE) mg/min, P < 0.05]. The rate of lactate conversion to glucose was double the normal rate (96 +/- 21 vs. 46 +/- 10 mg/min, P < 0.05). Increased gluconeogenesis from plasma lactate correlated with total glucose production (r = 0.74), with plasma lactate contributing to 58% of glucose production in obese children vs. 38% in normal children (P < 0.05). Conversion into glucose correlated with the rate of lactate release in the circulation (r = 0.76). In turn, the obese children converted a larger fraction (35 +/- 2 vs. 27 +/- 2%, P < 0.02) and amount (58 +/- 10 vs. 34 +/- 5 mg/min, P < 0.05) of glucose into plasma lactate. The amount of lactate originating from plasma glucose correlated (r = 0.70) with lipid oxidation, which was increased in the obese children (58 +/- 4 vs. 23 +/- 5 mg/min, P < 0.02). Our data suggest that increased gluconeogenesis from lactate is associated with increased lipid oxidation and could contribute to the progressive development of insulin resistance and glucose intolerance in juvenile obesity.
Stunff
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Institut National de la Santé et de la Recherche Médicale Unité 342, René Descartes University, Hôpital Saint Vincent de Paul, Paris, France.
Bougnères
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D020155:3-Hydroxybutyric Acid; D001786:Blood Glucose / Q000378:metabolism*; D002153:Calorimetry, Indirect; D002247:Carbon Isotopes; D002648:Child; D002675:Child, Preschool; D002952:Citric Acid Cycle; D003903:Deuterium; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005943:Gluconeogenesis; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D006885:Hydroxybutyrates / Q000097:blood; D007328:Insulin / Q000097:blood; D007773:Lactates / Q000097:blood* / Q000378:metabolism; D008066:Lipolysis; D008954:Models, Biological; D009765:Obesity / Q000097:blood / Q000378:metabolism*; D012016:Reference Values; D015430:Weight Gain
D001786:Blood Glucose; D002247:Carbon Isotopes; D005230:Fatty Acids, Nonesterified; D006885:Hydroxybutyrates; D007328:Insulin; D007773:Lactates; D003903:Deuterium; D005947:Glucose; D020155:3-Hydroxybutyric Acid