Effect of Growth Hormone on the Large-Particle Content of Rat Liver

Abstract

IN the course of an investigation¹ of rat liver, with respect to hormonal effects on the yield and composition of fractions isolated by differential centrifugation in 0.25 M sucrose medium², determinations have been made of the particle number in freshly isolated ‘large-particle’ (‘mitochondrial’) fractions. These fractions were obtained from liver homogenates, prepared with a Potter-type homogenizer and centrifuged at a low speed to remove ‘debris’ containing the nuclei, by farther centrifugation for 20 min. in an ‘Angle 13’ (Measuring and Scientific Equipment, Ltd.) centrifuge at 12,000 g (maximum value, at extreme tip of tube). The particles were suspended in 1.8 M sucrose solution and counted under dark-ground illumination as described by Allard et al. ³. Under these conditions (in 1.8 M sucrose) the particle size-range is decreased (compressed); all visible particles up to and including the mitochondrial size-range were counted.