Metabolism of Lactate Isomers by Rat and Sheep Liver and Rumen Epithelial Tissue

Publisher Website
Google Scholar
Abstract
Liver slices from 24-hr.-fasted male albino rats, and liver slices and rumen epithelial dices from 6O-hr.-fasted male Suffolk sheep were incubated for 2 hr. in the presence of L(+)- and D(-)-lactates. At the end of each incubation period, the media were analyzed for total and L (+)-lactic acid and total ketone body content. Both lactate isomers were metabolized by the liver slices of the fasted rats with a two-to-threefold greater utilization of the L(+)-lactate. The liver slices of the fasted sheep utilized noticeable quantities of the L(+)-isomer, but utilized little to none of the D(-)-lactate. Ketone body formation was depressed when either lactate isomer was present in rat liver slice medium; depression was more noticeable in the media containing the L(+)-enantiomorph. The ketone body content varied in the incubations with liver slices of fasted sheep. Neither lactate isomer was utilized by the rumen epithelial dices of the fasted sheep, but ketone bodies were synthesized. Samples of rumen contents were taken via a permanent rumen fistula. Strained rumen fluid was incubated for 4 hr. in the presence of glucose. The clarified incubated media were analyzed for total and L(+)-lactate acid. Approximately 40% of the lactate produced during the fermentation of glucose by the rumen microorganisms was D(-)-lactate. Copyright © 1967. American Society of Animal Science . Copyright 1967 by American Society of Animal Science