PROTEIN G-HORSERADISH PEROXIDASE BASED METHOD FOR LIGHT-MICROSCOPE IMMUNOCYTOCHEMISTRY - APPLICATION TO THE PITUITARY-GLAND OF THE KILLIFISH, FUNDULUS-HETEROCLITUS

Horseradish peroxidase-protein G conjugate was used to localize anti-h uman luteinizing hormone and anti-human chorionic gonadotropin primary antibodies bound to gonadotropins in paraffin and Historesin embedded sections of Fundulus heteroclitus pituitaries. The sensitivity and sp ecificity of this method and those obtained after the avidin-biotin-pe roxidase complex, the streptavidin-biotin-peroxidase complex and the p eroxidase-antiperoxidase procedures were compared. The protein G-horse radish peroxidase method gave a clear immunostaining of gonadotrophic cells with virtually no background. Detection efficiency was reduced i n comparison with the other techniques. As for the embedding medium, h ydrophilic resin Historesin considerably enhanced the structural detai l and the resolution of the immunostaining at light-microscope level.