Investigation Of Factors With Modulatory Effects On The Proliferatton Of Rat Anterior Pituitary Cells In Vitro

By the combined use of techniques such as cell culture, isotope incorporation , immunocytochemistry alone or plus autoradiography , in situ hybridization and radioimmunoassay, the present study was undertaken to investigate various factors capable of modulating the proliferation of rat anterior pituitary cells in vitro , as assessed by tritiated thymidine incorporation rates, percentages of immunostained cells , autoradiographic labelling and double-labelling indices and other parameters. It was found that : 1. the basal proliferative activity of cultured AP cells remained at a low level under the conditions used, resembling somewhat in vivo behaviour of AP cells. 2. Substance P and related tachykinins could dose-dependently increase the incorporation of ~3H-TdR into AP cells. The action of substance P was completely blocked by a substance receptor antagonist, spantide. The target cells of substance P only constitute a portion of AP cell populations, which are mainly folliculostellate cells as judged by anti-S-100 protein immunostaining and double-labelling index. 3. Dose-dependent proliferative actions could be also observed with the use of cytokines such as rhTNF-a and IL-2, with the former action being neutralized by specific McAb against...