Abstract
ABSTRACT.: We have analyzed the lα,25-dihydroxycholecalciferol [1,25(OH)2D3] receptor content of cultured cells from human amniotic fluid. Six cell lines were grown to confluence in a minimum essential medium containing 20% fetal calf serum. All had a normal karyotype, five were male and one was female. Hypertonic cytosol extracts were prepared by sonication followed by centrifugation at 200,000 × g 30 min. Saturation analysis was performed by incubating the extracts with [3H]-1,25(OH)2D3 (20-500 pM, 160 Ci/mmol) with and without 100-fold molar excess of unlabeled 1,25(OH)2D3. Linear sucrose gradient (5- 20% w/v) analysis was performed with 1.5 nM [3H]- 1,25(OH)2D3 alone or in presence of 100-fold molar excess, 1,25(OH)2D3. Functional responsiveness was measured by induction of 25-hydroxycholecalciferol-24R-hydroxylase with 1 and 10 nM 1,25(OH)2D3. The six cell lines studied had receptors with dissociation constant of 44 ± 6 pM (mean ± SEM). The binding capacity was 10,200 ± 1,750 sites/ng protein (mean ± SEM) with extreme values of 4,700 and 15,500. A single peak for specific binding migrating at approximately 3S was observed by sucrose gradient centrifugation. 25-Hydroxycholecalciferol-24R-hydroxylase was induced by 1 and 10 nM 1,25(OH)2D3 in a dose-dependent fashion. The data show that receptors for 1,25(OH)2D3 are present in cultured amniotic fibroblast like cells early in pregnancy. These cells may thus prove to be useful for further characterization of 1,25(OH)2D3 receptors in fetal tissue.
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Delvin, E., Pilon, AM. & Vekemans, M. Specific 1,25-Hydroxycholecalciferol Receptors and Stimulation of 25-Hydroxycholecalciferol- 24R Hydroxylase in Human Amniotic Cells. Pediatr Res 21, 432–435 (1987). https://doi.org/10.1203/00006450-198705000-00002
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DOI: https://doi.org/10.1203/00006450-198705000-00002