Specific 1,25-dihydroxyvitamin D3 binding sites in choroid plexus.
Quantitative autoradiographic analysis of [3H] 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) binding in vitamin D deficient mice provided evidence for high levels of specific binding in choroid plexus and, to a lesser extent, ventral hippocampus. Sucrose gradient analysis yielded a 3-4S peak of specific [3H]1,25(OH)2D3 binding in bovine choroid plexus, but not amygdala or hippocampus. Scatchard analysis of [3H]1,25(OH)2D3 binding in bovine choroid plexus yielded KD = 0.23 +/- 0.06 nM and Nmax = 43.5 +/- 0 fmol/g tissue (n = 5). This result indicates the presence of significant receptor-like [3H]1,25(OH)2D3 binding sites in the choroid plexus and, thus, suggests roles for this hormone in regulating the entry of calcium into the brain and/or in the central regulation of calcium homeostasis.
Walters
M R
MR
Department of Physiology, Tulane Medical School, New Orleans, LA 70112.
Fischette
C T
CT
Fetzer
C
C
May
B
B
Riggle
P C
PC
Tibaldo-Bongiorno
M
M
Christakos
S
S
D000818:Animals; D001665:Binding Sites; D002117:Calcitriol / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002417:Cattle; D002499:Centrifugation, Density Gradient; D002831:Choroid Plexus / Q000737:chemistry* / Q000378:metabolism; D006624:Hippocampus / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D051379:Mice; D051381:Rats; D018167:Receptors, Calcitriol; D011987:Receptors, Steroid / Q000032:analysis* / Q000378:metabolism
D018167:Receptors, Calcitriol; D011987:Receptors, Steroid; D002117:Calcitriol; D002118:Calcium