TETRAMETHYLBENZIDINE POLYVINYLPYRROLIDONE PLATINUM REACTION FOR DETECTION OF TRACER HORSERADISH-PEROXIDASE

3,3',5.5'-tetramethylbenzidine polyvinylpyrrolidone platinum (TMB-PVP- PT) reaction was moderately sensitive to horseradish peroxidase (HRP), and gave an improved image of the tracer localization. When HRP-injec ted mouse liver and submandibular gland specimens were treated with th is reagent, a blue reaction product in fine granular shape was formed only at the sites where the tracer was localized. while no endogenous peroxidase activity was detected at all. Some attempt to enhance the s ensitivity of this reagent to peroxidase was also made. This reaction was suitable for making permanent microscopic preparations.