Ma. Tetrick et al., CONTRIBUTION OF D-(-)-3-HYDROXYBUTYRATE TO THE ENERGY-EXPENDITURE OF NEONATAL PIGS, The Journal of nutrition, 125(2), 1995, pp. 264-272
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 r
andomly assigned to a 12 h continuous infusion of 3HB at 19.5, 37.8 55
.8 or 74.5 mu mol/min along with similar to 31 kBq/h of [3-C-14]3HB. P
iglets were housed in respiration chambers allowing collection of tota
l expired CO2 over 20-min intervals for the 12 h infusion and 6 h wash
out. Oxidation of 3HB was calculated from the quantity and specific ra
dioactivity of expired CO2 for 20-min collection periods at 6, 9 and 1
2 h for each piglet and collectively plotted against plasma 3HB concen
tration measured in blood drawn during those 20-min periods. A Linewea
ver-Burk plot of these data yielded a K-m of 0.62 +/- 0.07 mmol/L and
V-max 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 oxi
dation is a linear function of plasma concentration in the physiologic
range measured in piglets (0.006 mmol/L to 0.1 mmoI/L) and within thi
s range would account for 0.3% to 4.5% of piglet energy requirement. O
xidation of 3HB can meet a maximum of 30 to 40% of piglet energy requi
rement at unphysiologically high 3HB concentrations (>3 mmol/L).