Regulation of hepatic fructose 2,6-bisphosphate concentrations and lipogenesis after re-feeding in euthyroid and hyperthyroid rats. A regulatory role for glycogenesis.
The time courses of restoration of fructose 2,6-bisphosphate (Fru-2,6-P2) concentrations and rates of lipogenesis after chow re-feeding were correlated with glycogen concentrations and rates of glycogen synthesis in livers of 48 h-starved euthyroid and hyperthyroid rats. Although a regulatory function for glycogen in the regulation of Fru-2,6-P2 concentrations was excluded, an inverse relationship between rates of glycogenesis and Fru-2,6-P2 concentrations indicated a role for glycogenesis in the suppression of Fru-2,6-P2 concentrations during the early (0-4 h) period of re-feeding. There was also a negative correlation between rates of glycogenesis and lipogenesis, and a positive correlation between glycogen concentrations and the lipogenic rate. Decreased rates of glycogenesis in hyperthyroid rats were associated with increased rates of lipogenesis. The response of Fru-2,6-P2 to changes in the glycogenic rate was modified by hyperthyroidism, although a negative correlation was again observed.
Department of Chemical Pathology, London Hospital Medical College, U.K.
M J
MJ
Holness
E B
EB
Cook
M C
MC
Sugden
D000818:Animals; D005227:Fatty Acids / Q000096:biosynthesis; D005260:Female; D005502:Food; D005635:Fructosediphosphates / Q000378:metabolism*; D006598:Hexosediphosphates / Q000378:metabolism*; D006980:Hyperthyroidism / Q000378:metabolism*; D008055:Lipids / Q000096:biosynthesis*; D008099:Liver / Q000378:metabolism*; D008112:Liver Glycogen / Q000096:biosynthesis*; D051381:Rats; D011919:Rats, Inbred Strains; D013217:Starvation / Q000378:metabolism
D005227:Fatty Acids; D005635:Fructosediphosphates; D006598:Hexosediphosphates; D008055:Lipids; D008112:Liver Glycogen; C027652:fructose 2,6-diphosphate