Effect of dexamethasone and cytochrome P450 inhibitors on the formation of 7 alpha-hydroxydehydroepiandrosterone by human adipose stromal cells
- Resource Type
- Authors
- D.W. Killinger; B. Strutt; D. Vachon; M.W. Khalil
- Source
- The Journal of steroid biochemistry and molecular biology. 48(5-6)
- Subject
- medicine.medical_specialty
Endocrinology, Diabetes and Metabolism
Metabolite
Clinical Biochemistry
Dehydroepiandrosterone
Adipose tissue
Estrone
Biology
Biochemistry
Dexamethasone
chemistry.chemical_compound
Endocrinology
Glucocorticoid receptor
Internal medicine
medicine
Cytochrome P-450 Enzyme Inhibitors
Humans
Molecular Biology
Cells, Cultured
Metyrapone
Cell Biology
Aminoglutethimide
Mifepristone
Ketoconazole
chemistry
Adipose Tissue
Molecular Medicine
Stromal Cells
medicine.drug
- Language
- ISSN
- 0960-0760
7 alpha-Hydroxydehydroepiandrosterone (7 alpha-OHDHA) is a major metabolite of dehydroepiandrosterone (DHA) using adipose stromal cells. To gain a better understanding of the factors regulating DHA metabolism, we examined the effect of dexamethasone and cytochrome P450 inhibitors on the formation of 7 alpha-OHDHA. Dexamethasone (10(-9) to 10(-7) M) stimulated 7 alpha-OHDHA formation in a dose-dependent manner with a 2- to 5-fold stimulation at 10(-7) M. The dexamethasone stimulated 7 alpha-OHDHA formation was inhibited by RU486 in a dose-dependent manner with suppression to basal levels at 10(-6) M. Progesterone (10(-7) M) had no effect on 7 alpha-OHDHA formation suggesting that the dexamethasone stimulation was acting through the glucocorticoid receptor. Conversion of DHA to 7 alpha-OHDHA was inhibited by ketoconazole and metyrapone. An inhibition of 70-80% was obtained with ketoconazole and 25-60% with metyrapone at concentrations of 10(-5) M. Aminoglutethimide phosphate was less effective than either ketoconazole or metyrapone in inhibiting 7 alpha-OHDHA formation with30% inhibition at 10(-5) M. These studies indicate that 7-hydroxylation provides an alternative pathway for the metabolism of DHA in peripheral tissues. This pathway, which is regulated by glucocorticoids, may influence the amount of DHA available for conversion to androstenedione and its subsequent aromatization to estrone. The biological role of the 7-oxygenated metabolites and their effects on other steroidogenic pathways have not been established.