Specific 1,25-Hydroxycholecalciferol Receptors and Stimulation of 25-Hydroxycholecalciferol- 24R Hydroxylase in Human Amniotic Cells

Abstract

ABSTRACT. We have analyzed the la,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 Previous reports have shown that rat, murine, and human skin and cultured fibroblasts possessed an effector system for 1,25(OH)2D3 (1-5) suggesting that these tissues could serve as targets for the hormonal form of vitamin D3. Moreover, it has been established that these cells were responsive to 1 ,25(OH)2D3by showing an unequivocal stimulation of 24-OHase (6, 7).

Prenatal Diagnosis of Vitamin D-Dependent Rickets, Type II: Response to 1,25-Dihydroxyvitamin D in Amniotic Fluid Cells and Fetal Tissues

“…We found that amniotic fluid cells at midgestation contains specific high affinity 1,25-(OH) 2 D 3 receptors similar to those found in human cultured skin fibro-blasts and other responsive tissues (21). These findings are in agreement with those of Delvin et al (23) in six amniotic fluid cell cultures. These findings are in agreement with those of Delvin et al (23) in six amniotic fluid cell cultures.…”

Presence and binding characteristics of calcitriol receptors in human fetal gut

“…Data concerning such receptors in human gut is scarce and in fact, nonexistent for fetal tissues. The observed binding affinities and capacities for calcitriol in the epithelial cells from the proximal small intestine are similar to those reported for human adult jejunum [14] illustrating that the intestinal cells acquire this function very early during development. The binding affinities reported here are, however, slightly lower than those reported earlier for human cultured amniocytes [13].…”