Oscillatory behaviour and unsaturated fatty acid composition of diabetic liver mitochondria.

Volume oscillations of liver mitochondria resulting from valinomycin induced K+ transport, may be represented by the equation At/Am = C'.exp(-beta t).sin(omega 1t+ psi) where At is the oscillation amplitude at time t; Am, the maximal amplitude; beta, the damping coefficient, omega 1 the oscillation frequency, and C' and psi, constants. The kinetic parameters beta and omega 1 increased as a function of valinomycin concentration. Measurement of beta and omega 1 for mitochondria from normal rats (A); diabetic rats (B), and normal rats fed corn oil or lard-supplemented diets (C and D, respectively), yielded an increase in beta (P less than 0.05) in B and D as compared with A, and a decrease in omega 1 in B and D as compared with A and C, respectively. Analysis of mitochondrial lipids revealed significant diminution of arachidonic acid and other polyenoic fatty acids in diabetic and lard-fed rats, as compared with normal rats and corn oil-fed rats, respectively. The conclusion is drawn that the abnormal oscillatory behaviour of diabetic liver mitochondria is related to the alteration of the membrane fatty acid composition.