Expression and regulation of 6-phosphofructo-2-kinase/fructose- 2,6-bisphosphatase isozymes in white adipose tissue.
The aim of this work was to identify the 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFK-2/FBPase-2) isozyme(s) present in white adipose tissue. Ion-exchange chromatography of PFK-2 from rat epididymal fat pads yielded an elution pattern compatible with the presence of both the L (liver) and M (muscle) isozymes. This was consistent with a study of the phosphorylation of the purified adipose tissue enzyme by cAMP-dependent protein kinase, by specific labelling of the preparation with [2-32P]fructose 2,6-bisphosphate and by reaction with antibodies. Characterization of the PFK-2/FBPase-2 mRNAs showed that mature adipocytes express the mRNA that codes for the L isozyme and the two mRNAs that code for the M isozyme. Preadipocytes expressed mRNA that codes for the M isozyme. Incubation of rat epididymal fat pads with adrenaline stimulated glycolysis but decreased fructose 2,6-bisphosphate concentrations without significant inactivation of PFK-2. These results support previous findings showing that fructose 2,6-bisphosphate is not involved in the adrenaline-induced stimulation of glycolysis in white adipose tissue.
Bruni
P
P
Hormone and Metabolic Research Unit, Louvain University Medical School, Brussels, Belgium.
Vandoolaeghe
P
P
Rousseau
G G
GG
Hue
L
L
Rider
M H
MH
D000273:Adipose Tissue / Q000201:enzymology*; D000818:Animals; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004837:Epinephrine / Q000494:pharmacology; D006597:Fructose-Bisphosphatase / Q000235:genetics*; D005635:Fructosediphosphates / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics*; D006019:Glycolysis / Q000187:drug effects; D007527:Isoenzymes / Q000235:genetics*; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D008297:Male; D009097:Multienzyme Complexes / Q000235:genetics*; D009132:Muscles / Q000201:enzymology; D009206:Myocardium / Q000201:enzymology; D010732:Phosphofructokinase-1 / Q000235:genetics*; D025481:Phosphofructokinase-2; D010766:Phosphorylation; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar
D005635:Fructosediphosphates; D007527:Isoenzymes; D009097:Multienzyme Complexes; D012333:RNA, Messenger; C027652:fructose 2,6-diphosphate; D025481:Phosphofructokinase-2; D010732:Phosphofructokinase-1; D017868:Cyclic AMP-Dependent Protein Kinases; D006597:Fructose-Bisphosphatase; D004837:Epinephrine