Effect of repeated carbon monoxide intoxications on the myoglobin concentration in heart and skeletal muscle of rats.

A study was made to determine whether or not myoglobin plays a role in the adaptation response of an organism to chronic carbon monoxide exposure. Rats were injected subcutaneously with carbon monoxide (2.4 and 7.2 mmol CO/kg body weight, once daily on 5 days a week) 30times, 60times, or 107times. These exposure conditions resulted in carboxyhemoglobin concentrations of about 45 and 60%, respectively, as well as in an increase in both the hemoglobin concentration and the hematocrit. In skeletal muscle the myoglobin concentrations were not changed significantly, whereas the heart muscle showed an increase mean myoglobin concentration after the prolonged CO hypoxia (7.2 mmol CO/kg, 107times) by 54%.