Comparison of HDGF and HRP-3 expression. Antibodies against HDGF (A) or HRP-3 (B) were used to detect both proteins in the hippocampus of an adult mouse. Comparison of the double immunfluorescence demonstrates the lack of expression of HRP-3 in cells covering the ventricel wall of the hippocampal region (C, arrow), whereas HDGF is clearly expressed in this cell type. In contrast, hippocampal neurons coexpress both family members, but whereas HDGF is found to a similar extent in all neurons of the hippocampal formation (A), neurons of the dentate gyrus show only weak expression of HRP-3 when compared to the rest of the hippocampus (B). Higher magnification of this region demonstrates the existence of cells predominantly expressing HRP-3 (D, arrowheads) as well as a cell layer only positive for HDGF (D, arrows). CA: cornu ammonis; Sub: subiculum; DG: dentate gyrus; Bar in C is 80 μm; bar in D is 40 μm.