Mechanisms involved in the hormonal regulation of mitochondrial function through changes in the matrix volume

Abstract

The stimulation of liver mitochondrial metabolism by hormones that raise cytosolic [Ca 2+] can be explained, in part, by a 20–40% increase in mitochondrial volume which activates many enzymes associated with the inner membrane. The swelling is caused by a rise in mitochondrial [Ca 2+], inhibition of mitochondrial pyrophosphatase and a consequent increase in matrix [PP i]. PP i interaction with the adenine nucleotide carrier stimulates electrogenic transport of K + into the matrix. At higher [Ca 2+] nonspecific increases in permeability occur through a calcium-dependent interaction of peptidyl-prolyl cis-trans isomerase with the carrier. This can be blocked by cyclosporin A.