Protein synthesis in two mitochondrial populations isolated by isopycnic density centrifugation from normal and renoprival kidney

Abstract

During the 48 hours following mononephrectomy, there is a proliferation of mitochondria in the remaining kidney of the rat. Mitochondria from both normal and renoprival kidneys were separated by isopycnic density centrifugation into two distinct bands with mean densities of 1.178(M 1) and 1.162 (M 2). Using a dual-label procedure which reduces technical errors, the rates of mitochondrial protein synthesis of the fractions were compared. At 24, 48 and 72 hours post-mononephrectomy incorporation in vivo of leucine into M 1 was increased 35%, 58% and 29% and into M 2 50%, 85% and 14% over control. The results indicate a gradual shift in the rate of amino acid incorporation from M 2 to M 1 during mitochondrial formation.