Whole-body, peripheral and intestinal endogenous acetate turnover in dogs using stable isotopes.
Acetate metabolism supplies about 10% of energy requirements in food-deprived nonruminant animals. This study used a stable isotope dilution method to investigate the fate of acetate in 24-h food-deprived dogs free of colonic fermentation. Three dogs received intravenous bolus injections of 40 or 70 micromol/kg of [1-13C] acetate, and carotid blood was then sampled during a 15-min period to estimate the acetate distribution volume. Ten dogs received intravenous [1-13C] acetate infusions of 1.05 +/- 0.02 or 2.10 +/- 0. 10 micromol/(kg.min) for 120 or 200 min after a prime of 200 or 70 micromol/kg, respectively. Cephalic venous and carotid arterial blood were sampled for all dogs, and portal blood for five. Acetate distribution volume was 0.27 +/- 0.16 L/kg (mean +/- SEM). The concentrations of acetate in arterial (144 +/- 17 micromol/L), venous (155 +/- 20 micromol/L) and portal plasma (131 +/- 16 micromol/L) were not significantly different during infusion, whereas isotopic enrichments [mole percent excess (MPE): labeled acetate/all acetate molecules] in portal (1.2 +/- 0.2 MPE) and venous plasma (1.7 +/- 0.3 and 2.6 +/- 0.7 MPE) were lower than in arterial plasma for both infusion rates (4.9 +/- 0.6 and 7.6 +/- 0.8 MPE, respectively, P < 0.005). Whole-body acetate turnover was 24.4 +/- 2.4 micromol/(kg.min). Fractional acetate extractions for forelimb and intestine were 62 +/- 7 and 72 +/- 6%, respectively, and the production for each organ was 0.3 and 1.1 micromol/(kg.min) respectively, similar to that of utilization (P > 0.05). It is concluded that the forelimb and intestine produce and utilize acetate as an energy source in 24-h food-deprived dogs free of colonic fermentation.
Pouteau
E
E
Human Nutrition Research Center, Metabolism Division, CHU, Nantes, France.
Dumon
H
H
Nguyen
P
P
Darmaun
D
D
Champ
M
M
Krempf
M
M
D000085:Acetates / Q000097:blood / Q000378:metabolism*; D000818:Animals; D001944:Breath Tests; D002247:Carbon Isotopes; D002339:Carotid Arteries; D004285:Dogs; D005260:Female; D005508:Food Deprivation; D005552:Forelimb / Q000098:blood supply; D006859:Hydrogen / Q000032:analysis; D007413:Intestinal Mucosa / Q000378:metabolism*; D008297:Male; D008697:Methane / Q000032:analysis; D011169:Portal Vein; D014680:Veins
D000085:Acetates; D002247:Carbon Isotopes; D006859:Hydrogen; D008697:Methane