Changes in the water, sodium and potassium content of rat-liver mitochondria during metabolism

Abstract

The ability of rat-liver mitochondria to do secretory work was demonstrated by incubating them in a medium which would support oxidative phosphorylation and maintaining them, during separation for analysis, in a state of active metabolism by centrifuging at room temp. On incubation in a medium containing L-glutamate, Mg ions, inorganic phosphate and adenosine 5[image] -phosphate (AMP) mitochondria maintained a higher concn. of Na and K ions than that of the external fluid and swelling was prevented. In the absence of AMP there was no concn. gradient, the water content rose from 80 to 90% and agglutination readily occurred. Swelling did not occur in the presence of AMP plus dinitrophenol, although oxidative phosphorylation was prevented. It is concluded that the secretory action of mitochondria is dependent on active metabolism in the presence of an external adenine nucleotide and is linked with the capacity for oxidative phosphorylation in some way at present unknown.