[Effect of freezing and thawing rates on Ca2+ transport in rat liver mitochondria]

The calcium-transport function of the rat liver mitochondria was studied as affected by the freezing and thawing rates. It is established that the active Ca2+ transport system is disturbed in the process of freezing-thawing. An extent of this system damage depends mainly in the sample thawing rate. Mitochondria frozen at any rate but thawed at a slow rate become practically unable to transport Ca2+. The fast and slow freezing and fast thawing decrease the Ca2+ accumulation rate and the "calcium capacity" of mitochondria and promote and untimely release of accumulated Ca2+. Disturbances of the mitochondria calcium-transporting function is due to an increase in the proton conductivity of the mitochondria internal membrane.