title: Combined hypertriglyceridemic and insulin-glucose clamps for the characterization of substrate oxidation and plasma elimination of a long-chain triglyceride emulsion in healthy men.
abstract: This study examines the effect of glucose and insulin on the plasma elimination rate and oxidation of a fat emulsion by using indirect calorimetry in conjunction with lipid and insulin-glucose clamp techniques. Ten healthy subjects were studied on 2 occasions in a randomized, open, crossover study. On one occasion, a hypertriglyceridemic (HTG) clamp was administrated alone; and, on the other, HTG and insulin-glucose (IG) clamps were administrated simultaneously. During HTG clamps, serum triglyceride (TG) concentration was maintained at 4 mmol × L(-1). During the IG clamp, insulin was administered at a rate of 20 mU × m(-2) × min(-1); and the glucose level was maintained at 7 mmol × L(-1). Continuous indirect calorimetry was carried out throughout the study period. The infusion rate required to maintain stable serum TG concentrations did not differ between the 2 clamps. Mean free fatty acid concentration was lower during the HTG/IG than during the HTG clamp (0.40 ± 0.04 vs 0.82 ± 0.07 mmol × L(-1); P < .001). However, the increases in β-OH-butyrate levels were significantly lower in the HTG/IG compared with the HTG clamp (0.09 ± 0.04 vs 0.55 ± 0.09 mmol × L(-1); P < .001). Energy expenditure and the respiratory quotient were significantly higher at steady state in the HTG/IG than in the HTG clamp: 1.47 ± 0.06 vs 1.34 ± 0.04 kcal × min(-1) (P < .01) and 0.85 ± 0.01 vs 0.79 ± 0.01 (P < .01), respectively. Insulin and glucose did not significantly change plasma TG disposal rate (P = .0987) or total lipid oxidation (P = .3204) in this metabolic situation with an abundant supply of both carbohydrates and lipids. β-OH-butyrate increased during both clamps, indicating an ongoing hepatic fatty oxidation despite the administration of glucose/insulin.
authors.affiliation: Department of Breast and Endocrine Surgery, Karolinska University Hospital-Solna, Stockholm, Sweden. viveca.aberg@ki.se
authors.forename: Viveca
authors.initials: V
authors.lastname: Åberg
authors.forename: Anders
authors.initials: A
authors.lastname: Thörne
authors.forename: Anders
authors.initials: A
authors.lastname: Alvestrand
authors.forename: Jörgen
authors.initials: J
authors.lastname: Nordenström
mesh_terms: D000328:Adult; D001481:Basal Metabolism / Q000502:physiology; D018592:Cross-Over Studies; D004655:Emulsions; D004734:Energy Metabolism / Q000502:physiology*; D015309:Glucose Clamp Technique / Q000379:methods*; D006262:Health; D006801:Humans; D015228:Hypertriglyceridemia / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism; D008297:Male; D008657:Metabolic Clearance Rate / Q000502:physiology; D010084:Oxidation-Reduction; D014280:Triglycerides / Q000008:administration & dosage* / Q000097:blood / Q000737:chemistry / Q000493:pharmacokinetics*; D055815:Young Adult
chemical_list: D004655:Emulsions; D007328:Insulin; D014280:Triglycerides