INTERACTIONS BETWEEN CORTICOSTEROIDS AND FRACTIONS OF MITOCHONDRIA AND NUCLEI FROM NORMAL RAT LIVER CELLS.
ARMY MEDICAL RESEARCH LAB FORT KNOX KY
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A study was made to investigate whether the interaction between corticosteroids and subcellular fractions is dependent on the structural integrity of such fractions and also to single out any specific biological structure responsible for the interaction. Preparation was made of subcellular fractions by differential centrifugation and sonoration. Continuous flow electrophoresis and multiple equilibrium dialysis techniques were utilized. The five fractions prepared from rat liver nuclei interact differently with corticosterone. The acid protein and the globulin fraction show the highest binding a very small amount of steroid was associated with the histone fraction. In the mitochondrial fractions the uptake of cortisol or corticosterone is associated almost entirely with the particulate fractions. Three electrophoretic protein peaks were obtained from mitochondria and two of these peaks display combining affinity for corticosterone. A definitive interaction exists between fractions of nuclei and mitochondria from liver cells with corticosterone or cortisol. The interaction with corticosterone is greater than with cortisol. The disruption of the subcellular fractions does not destroy their binding affinity for corticosteroids.