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Basal and insulin-mediated carbohydrate metabolism in human muscle deficient in phosphofructokinase 1.

Journal Article


Abstract


  • Biopsies were obtained from the quadriceps femoris muscle of two male patients deficient in phosphofructokinase (PFK) 1. In the basal state the patients had markedly higher contents of UDP-glucose (approximately 5-fold), hexose monophosphates (approximately 7- to 13-fold), inosine monophosphate (IMP) (approximately 15-fold), and fructose 2,6-bisphosphate (F-2,6-P2; approximately 6-fold) than controls. Fructose 1,6-bisphosphate was not detectable, and phosphocreatine was lower (33 and 54 mmol/kg dry wt) than in controls [72 +/- 4 (SD)]. Patients had normal fasting plasma glucose and insulin levels and basal glucose turnover rates and responded normally to a 75-g oral glucose challenge. Patients were also studied during euglycemic hyperinsulinemia (approximately 95 mg/dl; 40 and 400 mU.m-2.min-1). Whole body glucose disposal rates were normal during both insulin infusion rates. Biopsies taken after the 400 mU insulin infusion showed decreases in acetylcarnitine and citrate and increases in the fractional activity of glycogen synthase. It is suggested that the high basal levels of F-2,6-P2 are, at least partly, a consequence of the high levels of fructose 6-phosphate, which will stimulate flux through PFK-2 and inhibit fructose-2,6-bisphosphatase. The low phosphocreatine and high IMP contents indicate that carbohydrate availability is important for control of high-energy phosphate metabolism, even in the basal state. The insulin-mediated decreases in acetylcarnitine and citrate suggest an activation of the tricarboxylic acid cycle in skeletal muscle but an absence of the normal response to replenish these intermediates.

UOW Authors


  •   Lillioja, Stephen (external author)

Publication Date


  • 1991

Citation


  • Katz, A., Spencer, M. K., Lillioja, S., Yan, Z., Mott, D. M., Haller, R. G., & Lewis, S. F. (1991). Basal and insulin-mediated carbohydrate metabolism in human muscle deficient in phosphofructokinase 1.. The American journal of physiology, 261(4 Pt 1), E473-E478. doi:10.1152/ajpendo.1991.261.4.e473

Web Of Science Accession Number


Start Page


  • E473

End Page


  • E478

Volume


  • 261

Issue


  • 4 Pt 1

Place Of Publication


Abstract


  • Biopsies were obtained from the quadriceps femoris muscle of two male patients deficient in phosphofructokinase (PFK) 1. In the basal state the patients had markedly higher contents of UDP-glucose (approximately 5-fold), hexose monophosphates (approximately 7- to 13-fold), inosine monophosphate (IMP) (approximately 15-fold), and fructose 2,6-bisphosphate (F-2,6-P2; approximately 6-fold) than controls. Fructose 1,6-bisphosphate was not detectable, and phosphocreatine was lower (33 and 54 mmol/kg dry wt) than in controls [72 +/- 4 (SD)]. Patients had normal fasting plasma glucose and insulin levels and basal glucose turnover rates and responded normally to a 75-g oral glucose challenge. Patients were also studied during euglycemic hyperinsulinemia (approximately 95 mg/dl; 40 and 400 mU.m-2.min-1). Whole body glucose disposal rates were normal during both insulin infusion rates. Biopsies taken after the 400 mU insulin infusion showed decreases in acetylcarnitine and citrate and increases in the fractional activity of glycogen synthase. It is suggested that the high basal levels of F-2,6-P2 are, at least partly, a consequence of the high levels of fructose 6-phosphate, which will stimulate flux through PFK-2 and inhibit fructose-2,6-bisphosphatase. The low phosphocreatine and high IMP contents indicate that carbohydrate availability is important for control of high-energy phosphate metabolism, even in the basal state. The insulin-mediated decreases in acetylcarnitine and citrate suggest an activation of the tricarboxylic acid cycle in skeletal muscle but an absence of the normal response to replenish these intermediates.

UOW Authors


  •   Lillioja, Stephen (external author)

Publication Date


  • 1991

Citation


  • Katz, A., Spencer, M. K., Lillioja, S., Yan, Z., Mott, D. M., Haller, R. G., & Lewis, S. F. (1991). Basal and insulin-mediated carbohydrate metabolism in human muscle deficient in phosphofructokinase 1.. The American journal of physiology, 261(4 Pt 1), E473-E478. doi:10.1152/ajpendo.1991.261.4.e473

Web Of Science Accession Number


Start Page


  • E473

End Page


  • E478

Volume


  • 261

Issue


  • 4 Pt 1

Place Of Publication