INTRACELLULAR DISTRIBUTION OF COPPER IN THE LIVER OF THE RAT

Abstract

The absolute amount of copper in whole liver and its subcellular fractions decreases as the rat matures. The decrease in mitochondrial and nuclear fractions, which contain most of the copper in the liver of the newborn rat, is much greater than the decrease in the soluble and microsomal fractions. This results in a redistribution of the copper, in favor of the supernatant. In the adult rat, this fraction is about one-half the total copper content of the liver, with the content of nuclei, mitochondria, and microsomes following in that order. The intraperitoneal injection of copper sulfate or the feeding of a diet low in copper brings the copper content of the liver above and below normal levels, respectively, and affects the intracellular distribution as follows. In copper loading, mitochondria and nuclei hold most of the excess and the cytoplasm and microsomes accumulate much less. In copper deficiency, there is a greater loss of soluble and mitochondrial copper and there are minor losses in microsomes and nuclei. The copper concentration in subcellular fractions of the liver seems to be related to the total copper content of the organ rather than to the physiological state of the animal.