Immunostaining for the long leptin receptor isoform in the brush border of human enterocytes: formol fixed, paraffin embedded samples (A, B); paraformaldehyde (PAF) fixed, paraffin embedded samples (C, D); PAF fixed, cryostat sections (E, F). The brush border displayed immunostaining in the enterocytes of both intestinal villi (A, C–E) and crypts (B). The striated appearance of the brush border was evident (arrows). Immunostaining for the leptin receptor (E) was absent using preabsorbed antiserum (F). A, D: bars=14 μm; B, C, E, F: bars=35 μm.