TY - JOUR
T1 - A dual-isotope technique for determination of in vivo ketone body kinetics
AU - Miles, J. M.
AU - Schwenk, W. F.
AU - McClean, K. L.
AU - Haymond, M. W.
N1 - Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 1986
Y1 - 1986
N2 - 'Total ketone body specific activity' has been widely used in studies of ketone body metabolism to circumvent so-called 'isotope disequilibrium' between the two major ketone body pools, acetoacetate and β-hydroxybutyrate. Recently, this approach has been criticized on theoretical grounds. In the present studies, [13C]acetoacetate and β-[14C]hydroxybutyrate were simultaneously infused in nine mongrel dogs before and during an infusion of either unlabeled sodium acetoacetate or unlabeled sodium β-hydroxybutyrate. Ketone body turnover was determined using total ketone body specific activity, total ketone body moles % enrichment, and an open two-pool model, both before and during the exogenous infusion of unlabeled ketone bodies. Basal ketone body turnover rates were significantly higher using [13C]acetoacetate than with either β-[14C]hydroxybutyrate alone or the dual-isotope model (3.6 ± 0.5 vs. 2.2 ± 0.2 and 2.7 ± 0.2 μmol·kg-1·min-1, respectively, P < 0.05). During exogenous infusion of unlabeled sodium acetoacetate, the dual-isotope model provided the best estimate of ketone body inflow, whereas 14C specific activity underestimated the known rate of acetoacetate infusion by 55% (P < 0.02). During sodium β-hydroxybutyrate infusion, [13C]-acetoacetate overestimated ketone body inflow by 55% (P = NS), while better results were obtained with 14C β-hydroxybutyrate alone and the two-pool model. Ketone body interconversion as estimated by the dual-isotope technique increased markedly during exogenous ketone body infusion. In conclusion, significant errors in estimation of ketone body inflow were made using single-isotope techniques, whereas a dual-isotope model provided reasonably accurate estimates of ketone body inflow during infusion of exogenous acetoacetate and β-hydroxybutyrate. In addition, the dual-isotope technique can provide estimates of ketone body interconversion. The dual-isotope model may offer significant advantages over single-isotope methods for studying ketone body metabolism in vivo.
AB - 'Total ketone body specific activity' has been widely used in studies of ketone body metabolism to circumvent so-called 'isotope disequilibrium' between the two major ketone body pools, acetoacetate and β-hydroxybutyrate. Recently, this approach has been criticized on theoretical grounds. In the present studies, [13C]acetoacetate and β-[14C]hydroxybutyrate were simultaneously infused in nine mongrel dogs before and during an infusion of either unlabeled sodium acetoacetate or unlabeled sodium β-hydroxybutyrate. Ketone body turnover was determined using total ketone body specific activity, total ketone body moles % enrichment, and an open two-pool model, both before and during the exogenous infusion of unlabeled ketone bodies. Basal ketone body turnover rates were significantly higher using [13C]acetoacetate than with either β-[14C]hydroxybutyrate alone or the dual-isotope model (3.6 ± 0.5 vs. 2.2 ± 0.2 and 2.7 ± 0.2 μmol·kg-1·min-1, respectively, P < 0.05). During exogenous infusion of unlabeled sodium acetoacetate, the dual-isotope model provided the best estimate of ketone body inflow, whereas 14C specific activity underestimated the known rate of acetoacetate infusion by 55% (P < 0.02). During sodium β-hydroxybutyrate infusion, [13C]-acetoacetate overestimated ketone body inflow by 55% (P = NS), while better results were obtained with 14C β-hydroxybutyrate alone and the two-pool model. Ketone body interconversion as estimated by the dual-isotope technique increased markedly during exogenous ketone body infusion. In conclusion, significant errors in estimation of ketone body inflow were made using single-isotope techniques, whereas a dual-isotope model provided reasonably accurate estimates of ketone body inflow during infusion of exogenous acetoacetate and β-hydroxybutyrate. In addition, the dual-isotope technique can provide estimates of ketone body interconversion. The dual-isotope model may offer significant advantages over single-isotope methods for studying ketone body metabolism in vivo.
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U2 - 10.1152/ajpendo.1986.251.2.e185
DO - 10.1152/ajpendo.1986.251.2.e185
M3 - Article
C2 - 3526920
AN - SCOPUS:0022445449
SN - 0193-1849
VL - 251
SP - E185-E191
JO - American Journal of Physiology - Endocrinology and Metabolism
JF - American Journal of Physiology - Endocrinology and Metabolism
IS - 2 (14/2)
ER -