The influence of pH on Ca2+ exchange in ferret heart mitochondria.
The effect of pH changes on Ca2+ transport by isolated heart mitochondria was measured. Two components of Ca2+ transport were identified, an accumulation dependent on mitochondrial respiration and a Na+-dependent efflux. A decrease of pH over the range 7.7-6.7 reduced the initial rate and the total amount of respiration dependent Ca2+ accumulation. At pH 7.2 the [Na+] required to activate half-maximal efflux, k1/2, was 7.5 +/- 1.1 mM. Decreasing the pH over the range 7.7 to 6.9 increased the k1/2 from 3.6 to 11.6. The effect of acidosis was more profound on the respiration dependent Ca2+ uptake than the Na+-dependent efflux.
Fry
C H
CH
Department of Physiology, University of Bern, Switzerland.
McGuigan
J A
JA
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D005289:Ferrets; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008929:Mitochondria, Heart / Q000378:metabolism*; D010101:Oxygen Consumption
D002118:Calcium