Metabolism of D- and DL-beta-hydroxybutyrate by mouse embryos in vitro

Rates of 14CO2 production by mouse conceptuses in vitro from D- and DL-[3-14C]-beta-hydroxybutyrate (beta OHB) were determined during the period of organogenesis (days 9 through 12 of gestation) in the presence of 4 to 32 mmol/L DL-beta OHB. During this time period the rates 14CO2 production from D-beta OHB metabolism are concentration-dependent, increase on each day of gestation, and the site of metabolism appears to shift from the visceral yolk sac placenta to the embryo proper. In contrast to fetal and neonatal tissues, the rates of 14CO2 production from DL-beta OHB oxidation is significantly greater than from D-beta OHB suggesting that the utilization of the L-isomer may be equal to or greater than that of the D-form.