Fatty acid metabolism of the perfused caudate lobe from livers of fed and fasted non-pregnant and fasted late pregnant ewes.
1. Fatty acid metabolism has been compared in perfused liver lobes from fed and fasted non-pregnant sheep and fasted pregnant sheep to provide further information on the control of ketogenesis in this species. 2. Ketogenesis from exogenous palmitate was greatest in lobes from fasted pregnant sheep and least in lobes from fed non-pregnant sheep, whereas rates of ketogenesis from exogenous octanoate (0.4 mM) were similar in lobes from sheep in all three states. 3. High rates of ketogenesis from endogenous fatty acids occurred in perfused lobes from fasted pregnant sheep, apparently owing to enhanced lipolysis. 4. Activities of glycerol-3-phosphate acyltransferase, carnitine palmitoyl transferase (CPT) and other enzymes involved in ketone production did not change with physiological state; sheep differ markedly from rats in this respect. 5. The results suggest that the primary point of control of ketogenesis within the liver of sheep is at the level of CPT; the lack of change in maximum CPT activity suggests that control by modulators of this enzyme activity is even more important in sheep than in rats.
Butler
S M
SM
Hannah Research Institute, Ayr, Scotland, UK.
Faulkner
A
A
Zammit
V A
VA
Vernon
R G
RG
D000818:Animals; D002334:Carnitine O-Palmitoyltransferase / Q000378:metabolism; D004951:Esterification; D005215:Fasting; D005227:Fatty Acids / Q000378:metabolism*; D005260:Female; D005992:Glycerol-3-Phosphate O-Acyltransferase / Q000378:metabolism; D066298:In Vitro Techniques; D007657:Ketone Bodies / Q000096:biosynthesis; D008099:Liver / Q000378:metabolism*; D010477:Perfusion; D011247:Pregnancy; D012756:Sheep
D005227:Fatty Acids; D007657:Ketone Bodies; D005992:Glycerol-3-Phosphate O-Acyltransferase; D002334:Carnitine O-Palmitoyltransferase