Diminished parathyroid 1,25(OH)2D3 receptors in experimental uremia.
In Sprague Dawley rats, six days after subtotal nephrectomy, serum 1,25(OH)2D3 concentration was diminished (59.8 +/- 17.5 pg/ml vs. 121 +/- 48; P less than 0.01). Despite low circulating 1,25(OH)2D3 levels, maximal specific binding capacity for 1,25(OH)2D3 in parathyroid glands was diminished (Nmax 87.5 fmol/mg protein and 3.52 fmol/mg DNA vs. 143 fmol/mg protein and 4.75 fmol/mg DNA, respectively). There was no change of KD, apparent molecular size (sucrose density gradient) and DNA binding affinity (DNA cellulose chromatography) pointing to intactness of the receptor. Since 1,25(OH)2D3 is a potent negative feedback signal for parathyroids, the data are potentially relevant for the genesis of secondary renal hyperparathyroidism.
Merke
J
J
Department of Internal Medicine, University of Heidelberg, Federal Republic of Germany.
Hügel
U
U
Zlotkowski
A
A
Szabó
A
A
Bommer
J
J
Mall
G
G
Ritz
E
E
D000818:Animals; D002117:Calcitriol / Q000097:blood; D002499:Centrifugation, Density Gradient; D002846:Chromatography, Affinity; D004247:DNA / Q000378:metabolism; D008297:Male; D009929:Organ Size; D010280:Parathyroid Glands / Q000378:metabolism* / Q000473:pathology; D051381:Rats; D011919:Rats, Inbred Strains; D018167:Receptors, Calcitriol; D011987:Receptors, Steroid / Q000378:metabolism*; D014511:Uremia / Q000097:blood / Q000378:metabolism*
D018167:Receptors, Calcitriol; D011987:Receptors, Steroid; D004247:DNA; D002117:Calcitriol