Thermogenic endurance and development of metabolic cold adaptation in birds may critically depend on their ability to synthesize and use fatty acids (FA) as fuel substrates. Hepatic lipogenesis and the capacity to oxidize FA in thermogenic tissues were measured in cold-acclimated (CA) ducklings (Cairina moschata) showing original mechanisms of metabolic cold adaptation in the absence of brown a...

1. Administration of cycloheximide (an inhibitor of protein synthesis) to lactating rats raised the concentrations of amino acids, and in particular, the branched-chain amino acids (valine, leucine and isoleucine) in blood, liver and mammary gland. 2. Inhibition of protein synthesis increased the incorporation in vivo of L-[U-14C]leucine into lipids of mammary gland and liver. 3. Cycloheximide ...

The existence of adrenal cortical effects upon the metabolism of lipids is well substantiated, although their biochemical mechanism is as yet poorly understood (l-4). Perhaps the most striking demonstration of this relationship concerns hepatic synthesis of fatty acids, as illustrated by the experiments carried out by Brady et al. in 1951 (5, 6). These authors observed that the impaired lipogen...

In this paper we propose that regulation of the glucose/ insulin axis by diet will result in increased fattening at the marbling (intramuscular) depot. The pattern of fat accretion in the whole carcass is first described to emphasise that the marbling depot is relatively late maturing. The pathways of fat metabolism are then discussed with the aim of examining the possibility of regulating fat ...

As is true in nonruminants, high levels of dietary fat reduce in vitro rates of lipogenesis from acetate and glucose, increase in vitro rates of fatty acid release, reduce activities of enzymes associated with lipogenesis indicating a physiological adaptation, and increase lipoprorein lipase activities in adipose tissues from Iambs and steers. (

Animals can adapt to fluctuating food conditions by accumulating energy reserves and so reduce unfavourable effects of low food supply on their growth and survival. However, within the Hymenoptera, several parasitoid species have been shown to be unable to store excess energy in lipid reserves. This proposal addresses the question why these species forego the possibility to accumulate lipid res...

The rates of ketogenesis from endogenous substrates, butyrate or oleate, have been measured in isolated hepatocytes from suckling and weanling rats. Ketogenesis from endogenous substrate and from oleate decreased on weaning, whereas the rate from butyrate remained unchanged. It is concluded that the major site of regulation of ketogenesis during this period of development involves the disposal ...