DETECTION OF P-GLYCOPROTEIN MEDIATED MDR MXR IN CARCINUS-MAENAS HEPATOPANCREAS BY IMMUNO-GOLD-SILVER LABELING/

Carcinus maenas were sampled in the German Bight for immunohistochemis try, histology and parallel chemical analysis of organochlorines. Incu bations were performed with a monoclonal antibody against P-glycoprote in which mediates multixenobiotic resistance in order to develop MXR i n hepatopancreas. The data showed that MXR was highly, expressed at th e microvilli of epithelial cells while inside epithelial cells of the tubules MXR was restricted to a specific cell type, the transitional s tage between fibrillar (F) cells and blister (B) cells. These cells we re rich in lysosomes as was demonstrated by high acid phosphatase acti vity. In aging B cells, fusion events of the lysosomal compartment to one large vacuole were observed to he accompanied by a loss of MXR pro tein content. Subsequently, B cells were eliminated from the epitheliu m into the lumina where the cell debris was incorporated into the faec es. It is concluded that F/B cells appear to be specialized for accumu lation of toxic compounds and their digestion and elimination. (C) 199 8 Elsevier Science Ltd. All rights reserved.