Cytological Phosphorylase Locations in Rat Liver and Muscle as Shown by a Lead Precipitation Method

The method of Goldberg et al. (J. Nat. Cancer Inst., 13, 543, 1952) for phosphorylase was so modified as to yield reproducible and reliable results. Tissues were frozen in liquid nitrogen, sectioned in a cryostat at —22 C, immersed overnight in acetone at dry-ice temperature, coated with celloidin, incubated in a medium containing glucose-1-phosphate, NaF, acetate buffer pH 5.8, and lead nitrate with or without addition of adenosine 5'-phosphate, washed in water, and the stain developed with either dilute ammonium sulfide solution or an aqueous solution of I₂-KI, 1:2:300. The technique demonstrates phosphorylase activity in sarcoplasm and in cytoplasm of hepatic cells.