THE EFFECT OF LIGHT MICROSCOPIC FIXATIVES ON THE RETENTION OF GLYCOGEN IN PROTEIN MATRICES AND THE PARTICULATE STATE OF NATIVE GLYCOGEN

The percentage of glycogen fixed or retained (not extracted with water) in rat liver slices and in model systems by various fixatives has been studied. After homogenization of the fixed liver slices, more glycogen was retained in the residue of liver initially fixed with Rossman's fixative (70%) than with Bouin's fixative (50%); little glycogen was retained following fixation with 3.7% formaldehyde (12%). Macromolecular glycogen extracted from rat liver and exposed for 2-16 hr at 3°C to various fixatives was found to form a stable solution when resuspended in water. After an exposure to Rossman's fixative (pH 1.7), components of Rossman's fixative and 3.7% formaldehyde (pH 6), the resuspended glycogen retained its macromolecular state; an exposure to Bouin's fixative (pH 1.9) dispersed the glycogen into smaller particles similar to that observed following treatment with 0.1 N HCl (pH 1.5). Both the action of picric acid on proteins and the maintenance of the macromolecular state of glycogen during Rossman's fixation appear to facilitate the effective fixation of glycogen. A possible mechanism for the fixation of glycogen is discussed.