Evidence for in vivo upregulation of 1,25(OH)2 vitamin D3 receptor in human monocytes.
Mammalian cells increase net expression of 1,25(OH) 2D3 receptors after exposure to physiological concentrations of 1,25(OH) 2D3 in vitro. We examined specific binding of 1,25(OH) 2D3 by human monocytes before and after daily administration of 1.5-2 micrograms 1,25(OH) 2D3 p.o. for 3 days in 5 healthy normal D-replete probands. Median specific binding (Nmax) at baseline was 793 molecules/cell and 2052 or 2828 at 24h and 72h of 1,25(OH) 2D3 treatment respectively. The results suggest (a) upregulation of 1,25(OH) 2D3 receptors occurs in man and (b) monocyte preparations can be used to assess receptor regulation in vivo.
Merke
J
J
Department of Internal Medicine, University of Heidelberg, Federal Republic of Germany.
Nawrot
M
M
Hügel
U
U
Szabo
A
A
Ritz
E
E
D000328:Adult; D002117:Calcitriol / Q000378:metabolism*; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism; D006801:Humans; D008297:Male; D009000:Monocytes / Q000378:metabolism*; D010641:Phenotype; D018167:Receptors, Calcitriol; D011987:Receptors, Steroid / Q000378:metabolism*; D015854:Up-Regulation
D018167:Receptors, Calcitriol; D011987:Receptors, Steroid; D002117:Calcitriol