REDUCED HIGH-ENERGY PHOSPHATE LEVELS IN RAT HEARTS .2. EFFECTS OF SODIUM CYANATE

The effects of increased blood-O2 affinity, due to carbamylation of hemoglobin in vivo, on aerobic metabolism in the heart were studied in rats. Adult male rats were injected intraperitoneally 3 times weekly for 10 wk with sodium cyanate (60 mg/kg). Significant derangement of blood-O2 interaction was observed. O2-dissociation curves were left shifted by 13 mmHg (35.1-21.8), and the overall deoxygenation rate (k) was reduced 41% (6.142-3.624, s-1); P < 0.001 for each parameter. Heart ATP and PCr [phosphocreatine] levels were reduced (ATP: 19.4-16.7; PCr: 15.0-11.0, .mu.m/g dry wt; P < 0.001 for each). In addition, glycogen levels fell (161.4-112.9, .mu.m C6/g dry wt; P < 0.001). Myocardial lactate levels increased 54% (2.6-4.0, .mu./g dry wt; P < 0.01) in the cyanate-treated group. These findings strongly suggest a hypoxia-induced activation of glycolysis as a consequence of altered oxidative metabolism in rats treated with sodium cyanate.