Ontogeny of the 1,25-dihydroxyvitamin D3 receptor in fetal rat bone

Abstract

To gain insights into 1,25-dihydroxyvitamin D3 receptor (VDR) function during fetal bone development, we examined fetal rat tissues from gestational days 13-21 for the presence and distribution of VDR using immunohistochemistry. Prior to ossification, VDR epitopes were observed in the mesenchyme condensing to form skeletal tissues, on day 13 in the developing vertebral column and limbs, and on day 17 of gestation in developing calvaria. Immunostaining for VDR was seen in proliferating and hypertrophic chondrocytes and in osteoblasts of limb buds and the vertebral column by day 17 of gestation. In calvaria, VDR epitopes were observed in osteoblasts by gestational day 19. VDR immunostaining was also evident in the skin of fetal limbs at all gestational ages examined. We show for the first time that the VDR appears very early in the developing fetal rat skeleton, suggesting that the VDR, in concert with its ligand, 1,25-dihydroxyvitamin D3, may play a role in the differentiation of mesenchymal precursors into bone tissue.

Evaluating the impact of maternal vitamin D supplementation on sow performance: II. Subsequent growth performance and carcass characteristics of growing pigs1,2

“…The active form of the vitamin (1,25-OH2-D 3 ) must be derived from fetal sources, but little to no data are available about how the active form is metabolized in the fetus. However, Johnson et al (1996) and Endo et al (2003) both illustrated the presence of vitamin D nuclear receptors (VDR) within fetal bone and muscle tissues. This suggests that the active 1,25-OH2-D 3 metabolite plays a role in the fetal development of these tissues.…”

Evaluating the impact of maternal vitamin D supplementation: I. Sow performance, serum vitamin metabolites, and neonatal muscle characteristics1,2

“…Alternatively, Rortvedt and Crenshaw (2012) clearly demonstrated the impact of maternal vitamin D deficiency on subsequent pig kyphosis; however, visual impacts of maternal deficiency were not observed until after weaning. A previous study with rat (Johnson et al, 1996) fetuses detected vitamin D receptor within fetal tissues prior to ossification, alluding to the functional role of vitamin D in the proliferation and differentiation of chondrocytes in skeletal tissue. In the current study, the maternal vitamin D supplementation concentrations were well above those needed to induce a vitamin D deficiency in sows.…”

Differential Effects of Growth Hormone and Alfa Calcidol on Trabecular and Cortical Bones in Hypophysectomized Rats

“…Calcitriol is also a potent stimulator of osteoclastic bone resorption. The function includes stimulating differentiation and fusion of osteoclast progenitors and activating mature preformed osteoclast (13)(14)(15).1OHD is an analog of the calcitriol. It does not require renal hydroxylation but requires 25-hydroxylation in the liver for its conversion to calcitriol.…”