The role of vitamin D in chorioallantoic membrane calcium transport

Elaroussi, Mahmoud A.; Uhland‐Smith, Ann; Hellwig, Wendy; DeLuca, Hector F.

doi:10.1016/0005-2736(94)90135-x

Cited by 36 publications

(5 citation statements)

References 25 publications

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“…The yolk laminar spherules (similar to spherocrystals) which appeared in the turkey yolk sac during late development were considered as the calcium storage structures (Cheville and Coignoul, 1984). It was reported that the chorioallantoic membrane transported calcium from eggshell into embryonic circulation during the last week of incubation (Elaroussi et al, 1994). This was in accordance with our observation: the formation and development of spherocrystals was accelerated at the late stage of incubation and the amount of spherocrystals reached the maximum at the last 2-3 day of incubation.…”

Section: The Templation Model Of the Formation Of Spherocrystals And supporting

confidence: 94%

Yolk spherocrystal: The structure, composition and liquid crystal template

Tong

Wan

et al. 2008

Journal of Structural Biology

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Section: The Templation Model Of the Formation Of Spherocrystals And supporting

confidence: 94%

Yolk spherocrystal: The structure, composition and liquid crystal template

Tong

Wan

et al. 2008

Journal of Structural Biology

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“…Its actions are thought to be mediated by a nuclear receptor, the vitamin D receptor (VDR), which heterodimerizes with the retinoid X receptor and interacts with specific DNA sequences on target genes. The VDR is evolutionarily well conserved and is expressed early in development in amphibians (1), mammals (2), and birds (3,4). As well as being expressed in the intestine, the skeleton, and the parathyroid glands, the VDR is found in several tissues not thought to play a role in mineral ion homeostasis (5).…”

mentioning

confidence: 99%

Targeted ablation of the vitamin D receptor: An animal model of vitamin D-dependent rickets type II with alopecia

Pirro

Amling

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

874

655

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Vitamin D, the major steroid hormone that controls mineral ion homeostasis, exerts its actions through the vitamin D receptor (VDR). The VDR is expressed in many tissues, including several tissues not thought to play a role in mineral metabolism. Studies in kindreds with VDR mutations (vitamin D-dependent rickets type II, VDDR II) have demonstrated hypocalcemia, hyperparathyroidism, rickets, and osteomalacia. Alopecia, which is not a feature of vitamin D deficiency, is seen in some kindreds. We have generated a mouse model of VDDR II by targeted ablation of the second zinc finger of the VDR DNA-binding domain. Despite known expression of the VDR in fetal life, homozygous mice are phenotypically normal at birth and demonstrate normal survival at least until 6 months. They become hypocalcemic at 21 days of age, at which time their parathyroid hormone (PTH) levels begin to rise. Hyperparathyroidism is accompanied by an increase in the size of the parathyroid gland as well as an increase in PTH mRNA levels. Rickets and osteomalacia are seen by day 35; however, as early as day 15, there is an expansion in the zone of hypertrophic chondrocytes in the growth plate. In contrast to animals made vitamin D deficient by dietary means, and like some patients with VDDR II, these mice develop progressive alopecia from the age of 4 weeks.1,25-Dihydroxyvitamin D is the major steroid hormone that plays a role in mineral ion homeostasis. Its actions are thought to be mediated by a nuclear receptor, the vitamin D receptor (VDR), which heterodimerizes with the retinoid X receptor and interacts with specific DNA sequences on target genes. The VDR is evolutionarily well conserved and is expressed early in development in amphibians (1), mammals (2), and birds (3, 4). As well as being expressed in the intestine, the skeleton, and the parathyroid glands, the VDR is found in several tissues not thought to play a role in mineral ion homeostasis (5). Its precise functions in these tissues, as well as its developmental role, remain unclear.Insights into the physiological actions of 1,25-dihydroxyvitamin D have been obtained from studies in vitamin Ddeficient animals (6-10) as well as in humans with VDR mutations (11,12). These investigations have demonstrated that 1,25-dihydroxyvitamin D plays an important role in intestinal calcium absorption and that animals lacking the active hormone or its nuclear receptor develop hypocalcemia, rickets, osteomalacia, and hyperparathyroidism. Although skin changes similar to psoriasis have been observed in vitamin D-deficient rats (13), the alopecia observed in some kindreds with mutant VDRs has not been observed in vitamin D deficiency.We have generated an animal model of vitamin Ddependent rickets type II (VDDR II) by targeted ablation of DNA encoding the second zinc finger of the DNA-binding domain of the VDR. The resultant animals are phenotypically normal at birth; however, they develop hypocalcemia, hyperparathyroidism, and alopecia within the first month of life. MATERIALS AND METHODSGenera...

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“…The VDR forms heterodimers with the retinoid X receptor (RXR) and interacts with specific DNA sequences on the target gene 9 . The VDR is evolutionarily well conserved and is expressed early in development in amphibians, 10 mammals, 11 and birds 12,13 . The VDR is found in several tissues not thought to play a role in mineral ion homeostasis 14 .…”

Section: Discussionmentioning

confidence: 99%

Vitamin D‐dependent rickets Type II with alopecia: two case reports and review of the literature

Al-Khenaizan

Vitale

2003

Int J Dermatology

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Vitamin D-dependent rickets Type II is a rare autosomal recessive disorder. It usually presents with rachitic changes not responsive to Vitamin D treatment with elevated circulating levels of 1,25-Dihydroxyvitamin D3, thus differentiating it from Vitamin D-dependent rickets Type I. Alopecia of the scalp or the body is seen in some families with Vitamin D-dependent rickets Type II. This is usually associated with more severe resistance to Vitamin D. We report two Saudi brothers with this disease, and review the salient features of this disease with emphasis on the associated alopecia.

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The role of vitamin D in chorioallantoic membrane calcium transport

Cited by 36 publications

References 25 publications

Yolk spherocrystal: The structure, composition and liquid crystal template

Yolk spherocrystal: The structure, composition and liquid crystal template

Targeted ablation of the vitamin D receptor: An animal model of vitamin D-dependent rickets type II with alopecia

Vitamin D‐dependent rickets Type II with alopecia: two case reports and review of the literature

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