Our goal is to better understand the mechanisms of glucocorticoid action in relation to cellular nutrition. We will continue to investigate the interrelationships between the dietary cofactor Vitamin B6 and glucocorticoid receptor mechanisms in human cells. Observations indicate that physiological changes in the intracellular concentrations of pyridoxal phosphate can dramatically decrease the responsiveness of HeLa S3 cells to glucocorticoid administration. The mechanisms for this effect appear to involve direct modification of the receptor protein resulting in an inhibition of DNA binding as well as the down-regulation of glucocorticoid receptor number. We hypothesize that pyridoxal phosphate may be a physiological antagonist of glucocorticoid action. Therefore we wish to explore further the mechanisms of interaction of pyridoxal phosphate with glucocorticoid receptors.
Four specific aims are proposed to evaluate pyridoxal phosphate/glucocorticoid receptor interrelationships: 1) To evaluate, using dense amino acids and monoclonal antibodies to the receptor, the influence of Vitamin B6 status on the metabolism of the glucocorticoid receptor and potential non-binding precursors; 2) To study the regulation of glucocorticoid receptor mRNA and its stability as a function of cellular B6 status; 3) To evaluate the influence of cellular B6 status on glucocorticoid induced transcription, and; 4) To generate peptide maps of the steroid, DNA, and Vitamin B6 binding domains of purified human glucocorticoid receptor. These studies should thoroughly evaluate the inter-relations of Vitamin B6 and glucocorticoid receptor at the cellular and molecular levels and further our understanding of steroid hormone action.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK032459-07
Application #
3230866
Study Section
Endocrinology Study Section (END)
Project Start
1979-12-01
Project End
1989-07-31
Budget Start
1988-08-01
Budget End
1989-07-31
Support Year
7
Fiscal Year
1988
Total Cost
Indirect Cost
Name
University of North Carolina Chapel Hill
Department
Type
Schools of Medicine
DUNS #
078861598
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
Tully, D B; Allgood, V E; Cidlowski, J A (1994) Modulation of steroid receptor-mediated gene expression by vitamin B6. FASEB J 8:343-9
Tully, D B; Cidlowski, J A (1993) Protein-blotting procedures to evaluate interactions of steroid receptors with DNA. Methods Enzymol 218:535-51
Allgood, V E; Oakley, R H; Cidlowski, J A (1993) Modulation by vitamin B6 of glucocorticoid receptor-mediated gene expression requires transcription factors in addition to the glucocorticoid receptor. J Biol Chem 268:20870-6
Silva, C M; Cidlowski, J A (1992) The effect of oxidation/reduction on the charge heterogeneity of the human glucocorticoid receptor. J Steroid Biochem Mol Biol 41:1-10
Allgood, V E; Cidlowski, J A (1992) Vitamin B6 modulates transcriptional activation by multiple members of the steroid hormone receptor superfamily. J Biol Chem 267:3819-24
Burnstein, K L; Cidlowski, J A (1992) The down side of glucocorticoid receptor regulation. Mol Cell Endocrinol 83:C1-8
Burnstein, K L; Bellingham, D L; Jewell, C M et al. (1991) Autoregulation of glucocorticoid receptor gene expression. Steroids 56:52-8
Burnstein, K L; Jewell, C M; Cidlowski, J A (1991) Evaluation of the role of ligand and thermal activation of specific DNA binding by in vitro synthesized human glucocorticoid receptor. Mol Endocrinol 5:1013-22
Allgood, V E; Powell-Oliver, F E; Cidlowski, J A (1990) The influence of vitamin B6 on the structure and function of the glucocorticoid receptor. Ann N Y Acad Sci 585:452-65
Cidlowski, J A; Bellingham, D L; Powell-Oliver, F E et al. (1990) Novel antipeptide antibodies to the human glucocorticoid receptor: recognition of multiple receptor forms in vitro and distinct localization of cytoplasmic and nuclear receptors. Mol Endocrinol 4:1427-37

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