The Interaction ∗ between K Depletion and CO 2 Inhalation on Intracellular Bicarbonate Content

Abstract

Summary

Intracellular bicarbonate content ([HCO₃ ^-] _i ) of rat skeletal muscle was derived from CO₂ distribution in animals subjected to CO₂ inhalation and K deficiency applied singly and together. The objectives were to determine (i) whether or not [HCO₃ ^-] _i would be reduced in acidotic, low-K muscle, and (ii) whether the [HCO₃ ^-] _i increase due to CO₂ inhalation would be the same in normal and K-deficient animals. There was a 20% reduction in the CO₂-derived [HCO₃ ^-] _i of low-K muscle. A 20% reduction was also obtained when deriving [HCO₃ ^-] _i from DMO pH _i . The [HCO₃ ^-] _i increment due to CO₂ inhalation was sufficiently less in low-K muscle to yield, upon analysis of variance, a statistical interaction between the two stresses applied. This interaction was indicative of less buffering by low-K muscle. The data strongly suggest that the acidotic, low-K cell is defending against H⁺ whose origin is metabolic.