Related Experiment Videos
Developmental changes in rat kidney 1,25-dihydroxyvitamin D receptor.
N J Koszewski1, T A Reinhardt, D C Beitz
1Department of Biochemistry and Biophysics, Iowa State University, Ames 50011.
Biochemical and Biophysical Research Communications
|July 16, 1990
Summary
Aging alters kidney vitamin D receptor (VDR) forms in rats, affecting DNA binding. Aged rats show reduced VDR forms with lower DNA affinity compared to young rats.
Area of Science:
- Endocrinology
- Molecular Biology
- Gerontology
Background:
- The 1,25-dihydroxyvitamin D receptor (VDR) plays a crucial role in calcium homeostasis and gene regulation.
- Understanding age-related changes in VDR is important for addressing vitamin D deficiency and related health issues in aging populations.
Purpose of the Study:
- To investigate age-dependent alterations in the rat kidney VDR.
- To characterize differences in VDR binding affinity to DNA between young and aged rats.
Main Methods:
- Cytosol preparation from young and aged Fischer 344 rat kidneys.
- DNA-cellulose binding assays to assess VDR-DNA interaction.
- DNA-cellulose chromatography and immunoblot analysis to identify VDR forms.
Main Results:
- No significant difference in unoccupied VDR levels between young and aged rats.
- Aged rats exhibited significantly lower VDR binding to DNA-cellulose compared to young rats (24% vs. 44%).
- Immunoblot analysis revealed two VDR bands (52K and 50K) in young kidneys, with the 50K form diminished in aged kidneys; the 50K form showed higher DNA affinity.
Conclusions:
- Rat kidneys possess two VDR forms with distinct DNA binding affinities.
- Aging leads to a reduction in the higher-affinity 50K VDR form in rat kidneys, impacting DNA binding capacity.