Ketogenesis in the liver of ruminants – adaptations to a challenge

Abstract

The descriptive aspects of hepatic fatty acid metabolism, and of ketogenesis in particular, have been extensively described for ruminants. There is, however, a distinct lack of information on the more mechanistic aspects of the subject. The biochemical profile of the livers of ruminant species shows both similarities to, and striking differences from, that of simple-stomached animals. Consequently, it may not always be valid to extrapolate from the situation in, say, rat liver to that in ruminant liver in order to interpret experimental observations in ruminants. Of perhaps greater interest is the recognition that the adaptations in the ruminant system are important not only in enabling us to rationalize the physiological changes observed in ruminants, but are in themselves of interest in the analysis of metabolic regulatory strategies. Consequently, this review deals with the peculiarities of the regulation of hepatic ketogenesis in ruminants, and the biochemical mechanisms that may explain their existence.