Lead and some other metals in the histochemical demonstration of rat liver glycogen phosphorylase activity

Summary Lead in a concentration of 0.25 mM was tried as a histochemical trapping agent for inorganic phosphate, liberated in the reversible reaction catalyzed by the liver glycogen phosphorylase.The reaction product, formed during the incubation and made visible with ammonium sulphide, was totally extracted with -amylase. Iodine staining after incubation was completely negative.The inhibitory effect on liver phosphorylase activity of several other metals was also studied histochemically. It was found that the inhibition generally increased with the molecular weight and concentration of the metals. It is concluded that Fe⁺⁺ could be useful as a trapping agent instead of lead.