Contribution of D-(-)-3-hydroxybutyrate to the energy expenditure of neonatal pigs.
In vivo oxidation rate of arterially infused D-(-)-3-hydroxybutyrate (3HB) was measured in 1-2-d-old-piglets. Twelve piglets (1.4 kg) were randomly assigned to a 12 h continuous infusion of 3HB at 19.5, 37.8, 55.8 or 74.5 mumol/min along with -31 kBq/h of [3-14C]3HB. Piglets were housed in respiration chambers allowing collection of total expired CO2 over 20-min intervals for the 12 h infusion and 6 h washout. Oxidation of 3HB was calculated from the quantity and specific radioactivity of expired CO2 for 20-min collection periods at 6, 9 and 12 h for each piglet and collectively plotted against plasma 3HB concentration measured in blood drawn during those 20-min periods. A Lineweaver-Burk plot of these data yielded a Km of 0.62 +/- 0.07 mmol/L and Vmax of 0.74 +/- 0.02 mmol ATP equivalents/(min.kg 0.75) (parameter estimate +/- SD), which could account for 32% of the piglet mean total ATP turnover of 2.3 mmol/(min.kg 0.75). These data show that 3HB oxidation is a linear function of plasma concentration in the physiologic range measured in piglets (0.006 mmol/L to 0.1 mmol/L) and within this range would account for 0.3% to 4.5% of piglet energy requirement. Oxidation of 3HB can meet a maximum of 30 to 40% of piglet energy requirement at unphysiologically high 3HB concentrations (> 3 mmol/L).
Tetrick
M A
MA
Department of Nutritional Sciences, University of Wisconsin, Madison 53706.
Adams
S H
SH
Odle
J
J
Benevenga
N J
NJ
D020155:3-Hydroxybutyric Acid; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D004734:Energy Metabolism / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006801:Humans; D006885:Hydroxybutyrates / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism* / Q000494:pharmacology; D007261:Infusions, Intra-Arterial / Q000662:veterinary; D008297:Male; D010084:Oxidation-Reduction; D011897:Random Allocation; D013552:Swine / Q000378:metabolism*; D013997:Time Factors
D006885:Hydroxybutyrates; D000255:Adenosine Triphosphate; D020155:3-Hydroxybutyric Acid