Figure 4.

Immunostaining of the basolateral plasma membrane (BLPM) of enterocytes for the long leptin receptor isoform. (A-C: human duodenum, Bouin's fixation; D, E: rat jejunum, epon embedded). BLPM immunostaining for the leptin receptor (arrows) was observed in human enterocytes in both longitudinal (A) and cross/oblique (B) sections of the epithelium. (C) Immunolabelling of the BLPM disappeared with preabsorption of the antiserum. (D, E) In (D), immunolabelling of the BLPM was evident (arrows). Note that labelling was not present in the most apical lateral regions of cells where junctional complexes are known to exist in the plasma membrane. For this reason a “loop” can be observed systematically in the labelling (curved arrows). In preabsorbed sections (*, E), immunolabelling of the BLPM disappeared. Staining of the lamina propria (*, D) was not specific as it did not disappear after absorption of antiserum (E). Stars, widened intercellular basolateral spaces. Bars=14 μm.