[Comparative study on the dependence of quantitative results in the electron microscopic autoradiography on the type of developer (Microdol X, Phenidon) (author's transl)].

It was the aim of the investigation to compare quantitative results of electron microscopic autoradiographs after the use of different developers (Microdol X, Phenidon) adapting morphometrical methods. Erythroblasts of rabbit were tested after incorporation of 3H-uridine in vitro. Both developers showed the same tendency at higher rates of incorporation (basophilic erythroblasts and polychromatic erythroblasts). Using Phenidon, however, we could obtain only half the values for the individual cell components. At high rates of incorporation Microdol X results in an overlapping of the silver filaments. Thus, more distinct grains can be reached by Phenidon. At smaller rates of incorporation (orthochromatic erythroblasts) after using Phenidon a quantitative evaluation is however influenced by too many factors of uncertainty so that according to our investigations Microdol X is better suited for a quantitative evaluation of electron microscopic autoradiographs.