Color enhanced transmission electron micrograph of a hepatic cell from a fasted hamster after an injection of cortisone. In mammalian liver, glycogen appears in the form of coarse rosettes (blue) or alpha particles. These are not uniformly distributed in the cytoplasm but tend to be concentrated in areas that are rich in smooth endoplasmic reticulum. As seen in the accompanying micrograph, the glycogen occupies the interstices among the membrane-limited circular and elongated profiles of the reticulum.