TY - JOUR
T1 - Influence of vanadate on glycolysis, intracellular sodium, and pH in perfused rat hearts
AU - Geraldes, Carlos F G C
AU - Castro, M. Margarida C A
AU - Sherry, A. Dean
AU - Ramasamy, Ravichandran
N1 - Funding Information:
ADS acknowledges the support of NIH (HL 34557), the Meadows Foundation and Robert A. Welch Foundation (AT- 584). M.M.C.A.C. and C.F.G.C.G acknowledge support from JNICT (Portugal). (project PBIC/S/SAU/1623/92). R.R. acknowledges a Praxis XXI visiting fellowship from JNICT, Portugal. R.R is the recipient of a Career Development Award from the American Diabetes Association.
PY - 1997
Y1 - 1997
N2 - Vanadium compounds have been shown to cause a variety of biological and metabolic effects including inhibition of certain enzymes, alteration of contractile function, and as an insulin like regulator of glucose metabolism. However, the influence of vanadium on metabolic and ionic changes in hearts remains to be understood. In this study we have examined the influence of vanadate on glucose metabolism and sodium transport in isolated perfused rat hearts. Hearts were perfused with 10 mM glucose and varying vanadate concentrations (0.7-100 μM) while changes in high energy phosphates (ATP and phosphocreatine (PCr)), intracellular pH, and intracellular sodium were monitored using 31P and 23Na NMR spectroscopy. Tissue lactate, glycogen, and (Na+, K+)-ATPase activity were also measured using biochemical assays. Under baseline conditions, vanadate increased tissue glycogen levels two fold and reduced (Na+, K+)-ATPase activity. Significant decreases in ATP and PCr were observed in the presence of vanadate, with little change in intracellular pH. These changes under baseline conditions were less severe when the hearts were perfused with glucose, palmitate and β-hydroxybutyrate. During ischemia vanadate did not limit the rise in intracellular sodium, but slowed sodium recovery on reperfusion. The presence of vanadate during ischemia resulted in attenuation of acidosis, and reduced lactate accumulation. Reperfusion in the presence of vanadate resulted in a slower ATP recovery, while intracellular pH and PCr recovery was not affected. These results indicate that vanadate alters glucose utilization and (Na+, K+)-ATPase activity and thereby influences the response of the myocardium to an ischemic insult.
AB - Vanadium compounds have been shown to cause a variety of biological and metabolic effects including inhibition of certain enzymes, alteration of contractile function, and as an insulin like regulator of glucose metabolism. However, the influence of vanadium on metabolic and ionic changes in hearts remains to be understood. In this study we have examined the influence of vanadate on glucose metabolism and sodium transport in isolated perfused rat hearts. Hearts were perfused with 10 mM glucose and varying vanadate concentrations (0.7-100 μM) while changes in high energy phosphates (ATP and phosphocreatine (PCr)), intracellular pH, and intracellular sodium were monitored using 31P and 23Na NMR spectroscopy. Tissue lactate, glycogen, and (Na+, K+)-ATPase activity were also measured using biochemical assays. Under baseline conditions, vanadate increased tissue glycogen levels two fold and reduced (Na+, K+)-ATPase activity. Significant decreases in ATP and PCr were observed in the presence of vanadate, with little change in intracellular pH. These changes under baseline conditions were less severe when the hearts were perfused with glucose, palmitate and β-hydroxybutyrate. During ischemia vanadate did not limit the rise in intracellular sodium, but slowed sodium recovery on reperfusion. The presence of vanadate during ischemia resulted in attenuation of acidosis, and reduced lactate accumulation. Reperfusion in the presence of vanadate resulted in a slower ATP recovery, while intracellular pH and PCr recovery was not affected. These results indicate that vanadate alters glucose utilization and (Na+, K+)-ATPase activity and thereby influences the response of the myocardium to an ischemic insult.
KW - Glycolysis
KW - Intracellular sodium
KW - Ischemia-reperfusion
KW - NMR
KW - Perfused rat hearts
KW - Vanadate effects
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U2 - 10.1023/A:1006899932108
DO - 10.1023/A:1006899932108
M3 - Article
C2 - 9144318
AN - SCOPUS:8244241759
SN - 0300-8177
VL - 170
SP - 53
EP - 64
JO - Molecular and Cellular Biochemistry
JF - Molecular and Cellular Biochemistry
IS - 1-2
ER -