Compartmentation of acetyl CoA studied by analysis of tricarboxylic acid cycle acids and 3-hydroxybutyrate in bile of rats given [2,2,2-2H3]ethanol

Abstract

Acetate, 3-hydroxybutyrate, pyruvate, lactate, citrate, 2-oxoglutarate, succinate, fumarate and malate were analysed in rat bile by gas chromatography and gas chromatography/mass spectrometry of their O-melthyloxime-t-butyldimethylsilyl derivatives. The concentration of acetate increased to about 1.8 mmol/l after administration of [2,2,2-2H3]ethanol. Acetate was formed from ethanol to an extent of about 82% and retained all of the 2H at C-2, whereas 15% of the 2H had been lost in the tricarboxylic acid cycle intermediates and 24% in 3-hydroxybutyrate. Thus the exchange of 2H for 1H takes place after formation of acetyl CoA. For citrate and 3-hydroxybutyrate, 41% and 11% respectively was formed from [2,2,2-2H3]ethanol. These results indicate that different pools of acetyl CoA are used for the synthesis of ketone bodies and citrate, with the latter being derived from ethanol to a much larger extent. Smaller fractions of 2-oxoglutarate (16%) and succinate (5%) were derived from [2,2,2--2H3]ethanol, indicating significant contributions from amino acids.

Transfer of deuterium from [1,1-2H2]ethanol to steroids and organic acids in the rat testis

“…Lactate and 3-hydroxybutyrate were isolated from blood (100 psl) by a slightly modified method [24]. [2HJLactate (11 tg) was added as an internal standard and either [U-14C]lactate or 3hydroxy[3-'4C]butyrate was added to monitor the recovery.…”

“…On the other hand, deuterated hydroxy acids may be transported in blood from the liver and label steroids in the testes. This paper reports the results of analyses of the deuterium incorporation into selected steroids [4], organic acids from the citric acid cycle and other hydroxy acids [23,24] in the testis and into the acids in liver and blood of rats given the labelled ethanol. In addition to providing information on the transfer of deuterium from ethanol to steroids and organic acids, the analyses have allowed the identification of several hydroxy acids in the testis.…”