Changes in bone potassium in response to hypercapnia

¹ Department of Physiology, University of Minnesota, Minneapolis, Minnesota

Experiments were carried out on two groups of rats and one group of dogs for the purpose of determining the effect of hypercapnia on bone potassium. Rats that breathed 30% CO₂ for 4 hr did not show a statistically significant change in the concentration of potassium in compact bone. Four hours of breathing 30% CO₂ in dogs and 48 hr of 15% CO₂ in rats, however, resulted in an increase in bone potassium. Changes in potassium in bone and interstitial fluid were in the same direction but the magnitude of change in interstitial fluid was not sufficient to account for the change in bone. All of the experiments indicate that bone does not contribute to the hyperkalemia associated with respiratory acidosis since bone apparently takes up potassium which is being transferred to the extracellular fluid from other sources.