Swelling studies on liver mitochondria from essential fatty acid deficient rats

Abstract

Liver mitochondria from essential fatty acid deficient rats swell more rapidly, both spontaneously and in the presence of a number of swelling accelerators, than do normal mitochondria. ATP reverses the swelling of deficient mitochondria in 0.154 M KCl to a greater extent than it does with normal ones. Reversal effects with both mitochondria in the presence of Ca 2+ and thyroxine, are similar. Azide, amytal, and cyanide inhibit the swelling of normal mitochondria suspended in sucrose, but only partially prevent it in deficient ones. 0.01 M ATP prevented the swelling of deficient mitochondria in the presence of either 0.3 M sucrose or 0.154 M KCl, but prevented swelling of normal mitochondria only in the KCl. An (ATP + Mg 2+)-mitochondrial relationship appears to exist in the case of normal mitochondria that is not found in the deficient ones. EDTA, present in the medium throughout the process of preparation of mitochondria, prevents swelling in both deficient and normal ones. It is suggested that the swelling tendency in liver mitochondria from essential fatty acid deficient rats is associated with altered respiratory and/or phosphorylating mechanisms rather than with a membrane alteration.