Role of fructose-2,6-bisphosphate in cardiac glycolysis
To study whether changes in the content of fructose-2,6-bisphosphate (Fru-2,6-P/sub 2/) are important in the control of phosphofructokinase (PFK) and glycolysis in heart. As in liver, isolated rat hearts were perfused as either a Langendorff or working model with various glucose concentrations in the presence or absence of insulin. Glucose utilization was estimated from /sup 3/H/sub 2/O production from (3-/sup 3/H)glucose. Metabolite contents were measured and PFK was isolated from freeze-clamped hearts. Both cardiac work and insulin accelerated glycolysis 4 to 6 fold. Cellular contents of allosteric effects of PFK including ATP, AMP, Pi, Fru-1,6-P/sub 2/, and cytoplasmic citrate did not change or correlate with these increased rates. Increases in Fru-6-P availability and Fru-2,6-P/sub 2/ did appear to correlate with increased glycolytic rate. Higher Fru-6-P appeared more important in regulating the rate increase observed with insulin in Langendorff hearts, while Fru-2,6-P/sub 2/ appeared more important in mediating the increased rate seen with higher workload. In addition, PFK isolated from working hearts was less sensitive to ATP inhibition than PFK from Langendorff hearts. It is concluded that changes in Fru-6-P, Fru-2,6-P/sub 2/, and a covalent modification are important in the control of PFK activity and glycolysis in heart muscle, but the relative importance of the contributions appears to depend on the stimulus. The classic effectors of PFK activity probably play no role in such control.
- Research Organization:
- VA Medical Center, Dallas, TX
- OSTI ID:
- 7170698
- Report Number(s):
- CONF-8606151-; TRN: 86-039165
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:6; Conference: 76. annual meeting of the Federation of American Society for Experimental Biology, Washington, DC, USA, 8 Jun 1986
- Country of Publication:
- United States
- Language:
- English
Similar Records
Increasing the Thermodynamic Driving Force of the Phosphofructokinase Reaction in Clostridium thermocellum
Studies of anaerobic and aerobic glycolysis in Saccharomyces cerevisiae
Related Subjects
GLUCOSE
METABOLISM
PHOSPHATES
BIOCHEMICAL REACTION KINETICS
PHOSPHOTRANSFERASES
ENZYME ACTIVITY
FRUCTOSE
HEART
INSULIN
METABOLITES
PERFUSED ORGANS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
WATER
ALDEHYDES
BODY
CARBOHYDRATES
CARDIOVASCULAR SYSTEM
ENZYMES
HEXOSES
HORMONES
HYDROGEN COMPOUNDS
ISOTOPE APPLICATIONS
KETONES
KINETICS
LABELLED COMPOUNDS
MONOSACCHARIDES
ORGANIC COMPOUNDS
ORGANS
OXYGEN COMPOUNDS
PEPTIDE HORMONES
PHOSPHORUS COMPOUNDS
PHOSPHORUS-GROUP TRANSFERASES
REACTION KINETICS
SACCHARIDES
TRANSFERASES
550501* - Metabolism- Tracer Techniques