AJP - Endocrinology and Metabolism, Vol 253, Issue 5 E496-E502, Copyright © 1987 by American Physiological Society
Study of ketone body kinetics in children by a combined perfusion of 13C and 2H3 tracers
P. F. Bougneres and P. Ferre
Institut National de la Sante et de la Recherche Medicale U 188, Hopital Saint Vincent de Paul, Paris, France.
Ketone body kinetics were quantified in six children (3-5 yr old), who were
fasted for 13-22 h, by a combined perfusion of [3-13C]acetoacetate
([13C]AcAc) and D-(-)-beta-[4,4,4-2H3]hydroxybutyrate (beta-[2H3]OHB) and
gas chromatography-mass spectrometry analysis. Results were analyzed
according to the "single-pool" (combined enrichments) or the
"two-accessible pools" models. After 20-22 h of fasting, ketone body
turnover rate was 30-50 mumol.kg-1.min-1, a rate achieved after several
days of fasting in adults. At low ketosis, acetoacetate was the ketone body
preferentially synthesized de novo and utilized irreversibly. When ketosis
increased, acetoacetate irreversible disposal was not enhanced, since it
was largely converted into beta-OHB, whereas beta-OHB irreversible disposal
was very much increased. The single-pool and two-pool models gave similar
ketone body turnover rates when [13C]AcAc was the tracer, whereas the use
of beta-[2H3]OHB gave some more divergent results, especially at low
ketosis. These studies demonstrate that ketogenesis is very active in
short-term fasted children and that the use of a combined infusion of
[13C]AcAc and beta-[2H3]OHB is a convenient way to give insight into
individual ketone body kinetics.
