Glycogen synthesis in rat liver from a pool of free glucose.

Glycogen synthesis in isolated perfused livers or livers of anesthesized rats (in situ), was studied using radioactively labelled fructose, lactate, and inositol as substrates. The specific radioactivity of glucose and glycogen was measured at various times and compared with that of some intermediates. The results suggest that liver glycogen is formed from the pool of free glucose which in turn is fed by the so-called "direct and indirect pathway" of glycogen synthesis.

Biochemical effects and zonal heterogeneity of peroxisome proliferation induced by perfluorocarboxylic acids in rat liver.

Rats were treated for 5 to 14 days with perfluoroacetate, perfluorobutyrate and perfluorooctanoate. Alterations in hepatic morphology with special reference to the peroxisomal compartment were investigated by light and electron microscopy following cytochemical staining of catalase activity with the alkaline 3,3'-diaminobenzidine medium. All three compounds induced hepatomegaly and peroxisome proliferation.

Improved isolation and purification of rat liver peroxisomes by combined rate zonal and equilibrium density centrifugation.

Two different peroxisome preparations were isolated from male rat liver by using total homogenate (TH) as the starting material for one and the light mitochondrial (L) fraction for the other. The technique worked out is based on rate zonal (RZ) centrifugation in a sucrose gradient and subsequent isopycnic centrifugation in a Nycodenz gradient. The peroxisome fraction isolated from the L fraction consisted of 97-98% peroxisomal protein with catalase activity 49-fold enriched over TH.

Rat liver peroxisomes. I. New peroxisome population induced by thyroid hormones in the liver of male rats.

The paper presents results that a hyperthyroid state for 5 to 10 days induces a new peroxisome population in the liver of male rats. This assumption is based on the following observations: 1. Treatment of male rats for five consecutive days with 25 micrograms thyroxine per day resulted in an increase of catalase and D-amino acid oxidase activities by 32 and 61%, respectively.