The temporal distribution of the 1 alpha,25-dihydroxycholecalciferol receptor in the rat jejunal villus.
The distribution of the 1 alpha,25-dihydroxycholecalciferol receptor was studied in enterocytes isolated from the upper, mid and lower villus and crypt cells of the jejunum of normal and rachitic rats. In all cell fractions a high-affinity receptor (KD congruent to 0.07 nmol/l) with a sedimentation coefficient of 3.5S was demonstrated. In normal rats there was a 60% reduction in receptor numbers in crypt cells compared with the mid and upper villous cells. Vitamin D deficiency led to a reduction in receptor numbers in all cell fractions (45% upper villus, 78% crypt cells). The data are compatible with the concept of calcium absorption occurring in the differentiated villous cells and also account for the reduction in absorption in rachitic animals.
D000818:Animals; D001665:Binding Sites; D002117:Calcitriol / Q000378:metabolism; D002499:Centrifugation, Density Gradient; D002762:Cholecalciferol / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D066298:In Vitro Techniques; D007583:Jejunum / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D018167:Receptors, Calcitriol; D011987:Receptors, Steroid / Q000378:metabolism*; D013997:Time Factors; D014018:Tissue Distribution; D014808:Vitamin D Deficiency / Q000378:metabolism
D018167:Receptors, Calcitriol; D011987:Receptors, Steroid; D002762:Cholecalciferol; D002117:Calcitriol