DEMONSTRATION OF VITAMIN D RECEPTORS INNORMAL HUMAN DUODENAL BIOPSY SPECIMENSSucrose density gradient analysis - Figure 1shows the sucrose density gradient sedimentation profile of the 1,25-(OH)2 D3 receptorprepared by cytosol extraction from histologically normal duodenal biopsy specimens ofa single patient. The arrow points to the 14Covalbumin marker protein (3.6S). Radioactivity was associated with a sedimentationcoefficient of about 3.6S, totally quenched bythe addition of an excess of inert ligand. Thisis in good agreement with results reportedfor human vitamin D receptor in surgicalspecimens of the gut. 14