ANATOMICAL DISTRIBUTION OF BIOTIN-BINDING PROTEIN/AVIDIN IN THE HEN OVIDUCT

In laying hen oviduct tissues fixed with buffered-formaldehydes, the definitive localization of endogenous biotin-binding protein and immunogenic avidin was demonstrated in the cytoplasm of tubular gland cells and PAS-positive seromucous cells of the epithelium of the lower third magnum and the isthmus. Smaller amounts of the protein were also associated with tubular gland cells and deep-lining cells as crypt-constituents, excluding epithelial goblet-like cells, of the middle magnum. In biotin-affinity histochemistry, suppression by pre-incubation with biotin was evaluated to be the most satisfactory procedure for positive control stainings. The staining intensity and pattern achieved with biotinylated-horseradish peroxidase was more prominent than that achieved with biotinylated-alkaline phosphatase techniques. Positively stained profiles of tubular gland cells varied considerably with different cellular constituents, having a mosaic-like appearance. In addition, every biotin-binding site was not always stained by immunoperoxidase techniques. This paper discusses the reasons for these heterogeneous localizations resulting from these two staining procedures.