Decrease in myoglobin and enzyme contents with haemodilution in non-hypoxaemic polycythaemic patients

Quadriceps muscle biopsies from five patients with primary polycythaemia and four patients with non-primary polycythaemia, all with normal respiratory functions, were studied before and after normalization of haemoglobin and erythrocyte volume fraction by haemodilution or venaesectio. Since similar results were obtained from both groups of patients data were pooled. After normalization of the erythrocyte volume fraction myoglobin decreased by 19 +/- 16%, P less than 0.01, the activity of creatine kinase and citrate synthase by 12 +/- 8 and 14 +/- 18%, P less than 0.05, respectively. The decrease in myoglobin content was related to the decrease in haemoglobin concentration (r = 0.77, P less than 0.01). In conclusion, these data suggest that in non-hypoxaemic polycythaemia skeletal muscle shows adaptations indicative of an impaired oxygenation and a metabolic stress, adaptations that are reversed by haemodilution.