Functional and metabolic consequences of vitamin B-6 deficiency in the rat heart.
The cardiac functional and metabolic consequences of pyridoxine deficiency were studied in rats maintained on a pyridoxine-deficient diet for 10 weeks. Because food intake was diminished in the pyridoxine-deficient rats, a second group of animals was fed a diet restricted to the intake of the pyridoxine-deficient animals. The inotropic response (developed pressure) to an isoproterenol or Ca2+ concentration response curve was measured simultaneously with high energy phosphate levels using a modified Langendorf apparatus and 31P nuclear magnetic resonance spectroscopy. The inotropic response to Ca2+ and isoproterenol was significantly decreased relative to controls in both the food-deprived and the pyridoxine-deficient groups. Developed pressure after adrenergic stimulation was significantly less in the pyridoxine-deficient than in the food-deprived animals. Phosphocreatine and ATP levels were maintained and did not differ among the control, pyridoxine-deficient, and food-deprived groups during isoproterenol and Ca2+ stress, implying that the diminished inotropy was not due to an abnormality in generation of high energy phosphate levels.
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001835:Body Weight; D002118:Calcium / Q000502:physiology; D002149:Energy Intake; D006321:Heart / Q000033:anatomy & histology / Q000503:physiopathology*; D007545:Isoproterenol / Q000494:pharmacology; D009200:Myocardial Contraction; D009206:Myocardium / Q000378:metabolism*; D009929:Organ Size; D010725:Phosphocreatine / Q000378:metabolism; D051381:Rats; D026681:Vitamin B 6 Deficiency / Q000378:metabolism / Q000503:physiopathology*
D010725:Phosphocreatine; D000255:Adenosine Triphosphate; D007545:Isoproterenol; D002118:Calcium