The subcellular distribution of transferrin in rat choroid plexus studied with immunogold labelling of ultracryosections. Histochem J

Department A, Panum Institute, University of Copenhagen, Denmark.
The Histochemical Journal 09/1989; 21(8):441-8. DOI: 10.1007/BF01845793
Source: PubMed


Choroid plexus epithelium from third ventricle choroid plexus of 2-3-week-old rats was examined for transferrin-like immunoreactivity. In 5 microns paraffin sections most epithelial cells exhibited a pronounced immunoperoxidase staining for transferrin. The ultrastructure of the epithelium in question was examined by conventional electron microscopy. Immunolabelling of ultracryosections with IgG-gold, protein-A gold or protein-A gold-antiprotein-A protein-A gold showed an intense labelling of the basal extracellular space. The lateral intercellular space and the luminal surface showed a more variable labelling; no labelling of the tight junction zone was seen. Intracellularly a distinct labelling of the 'uptake and disposal pathway' (the endosomal-lysosomal system) was observed, but also the synthetic machinery (rough endoplasmic reticulum, stacked Golgi membranes) showed a characteristic labelling. Thus it seems likely that both uptake and synthesis of transferrin occur in choroid plexus epithelial cells.

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    • "Many studies have demonstrated the presence of proteins and mRNA for a large number of cytokines, growth factors and hormones in the choroid plexus, for example: interleukin-1β [8], interleukin-6 [9], Tumor Necrosis Factor (TNF)-α [10], IGF-I [11], NGF [12], IGF-II [13], Transforming Growth Factor (TGF)-α [14], TGF-β [15], Vascular Endothelial Growth Factor (VEGF) [16], transferrin [17], TTR [6,18], gelsolin [19] and vasopressin [20]. Most of these substances have their own receptors in the choroid plexus [21]. "
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