Related Experiment Videos
The ovary: a target organ for 1,25-dihydroxyvitamin D3
Abstract:
Using both clonal Chinese hamster ovary (CHO) cells in culture and the hen ovary, we have searched for the presence of specific 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] receptors. Receptor analyses were carried out on high salt cytosols of CHO cells and high salt extracts of hen ovarian nuclei that were originally isolated in low salt buffer. Both CHO and hen ovary contain a specific high affinity 1,25-(OH)2D3 receptor (Kd = 10(-10) - 10(-11) M), which sediments (3.3S) in high salt sucrose gradients identically to the chick intestinal receptor for 1,25-(OH)2D3. This 3.3S macromolecule from both sources absorbed to DNA-cellulose at 0.1 M KCl and eluted during a linear salt gradient at 0.2-0.22 M KCl, a property characteristic of the 1,25-(OH)2D3 receptor. Saturation analysis indicated that there are approximately 2000 copies of the receptor molecule per CHO cell. We also investigated the effect of 1,25-(OH)2D3 on ovarian cell growth in monolayer culture of CHO cells. Significant inhibition of CHO cell growth (up to 60%) was observed in the presence of physiological (100 pM) levels of 1,25-(OH)2D3 in the culture medium. This inhibition of growth was dose dependent and was accompanied by a parallel decrease in total cell protein. Concentrations of 25-hydroxyvitamin D3 and 24,25-dihydroxyvitamin D3 as high as 1 nM did not affect CHO cell growth, indicating that, like receptor binding, cell proliferation is selectively influenced by 1,25-(OH)2D3 over other vitamin D metabolites. These data demonstrate that ovarian cells in mammals and birds possess the 1,25-(OH)2D3 receptor which may play a role in the effect of 1,25-(OH)2D3 on the growth of these cells in culture.
Insights
Researchers found specific 1,25-dihydroxyvitamin D3 receptors in both Chinese hamster ovary (CHO) cells and hen ovaries. This vitamin D metabolite selectively inhibits ovarian cell growth, suggesting a role in reproductive health.
Area of Science:
- Endocrinology
- Cell Biology
- Reproductive Biology
Background:
- The role of vitamin D metabolites in reproductive tissues is not fully understood.
- Specific receptors for 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] are known to exist in various tissues.
- Investigating these receptors in ovarian cells could reveal novel regulatory mechanisms.
Purpose of the Study:
- To identify and characterize 1,25-(OH)2D3 receptors in ovarian cells.
- To determine the effect of 1,25-(OH)2D3 on ovarian cell growth.
- To elucidate the potential role of 1,25-(OH)2D3 in ovarian function.
Main Methods:
- Receptor analysis using high salt cytosols and nuclear extracts from Chinese hamster ovary (CHO) cells and hen ovaries.
- Sucrose gradient sedimentation and DNA-cellulose chromatography to characterize receptor binding.
- Monolayer culture of CHO cells to assess the impact of vitamin D metabolites on cell proliferation.
Main Results:
- Specific high-affinity 1,25-(OH)2D3 receptors (Kd = 10(-10) - 10(-11) M) were detected in both CHO cells and hen ovaries.
- The receptor exhibited properties consistent with the chick intestinal 1,25-(OH)2D3 receptor, including sedimentation and DNA-binding characteristics.
- Physiological levels of 1,25-(OH)2D3 significantly inhibited CHO cell growth (up to 60%) in a dose-dependent manner.
- Other vitamin D metabolites, such as 25-hydroxyvitamin D3 and 24,25-dihydroxyvitamin D3, did not affect cell growth.
Conclusions:
- Mammalian and avian ovarian cells possess specific 1,25-(OH)2D3 receptors.
- 1,25-(OH)2D3 selectively inhibits ovarian cell growth.
- These findings suggest a potential role for 1,25-(OH)2D3 in regulating ovarian cell proliferation and function.