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Steroid metabolism by epidermal keratinocytes
L Milewich1, C B Shaw, R D Sontheimer
1Department of Obstetrics-Gynecology, University of Texas Southwestern Medical Center, Dallas 75235-9051.
Annals of the New York Academy of Sciences
|January 1, 1988
Summary
Human epidermal keratinocytes metabolize steroids, expressing key enzymes like sulfatase and 17 beta-hydroxysteroid oxidoreductase (17 beta-HSOR). This reveals their role in steroid biotransformation and potential skin-related functions.
Area of Science:
- Biochemistry
- Dermatology
- Cell Biology
Background:
- Human epidermal keratinocytes play a role in skin homeostasis.
- Understanding their metabolic capabilities is crucial for dermatological research.
- Steroid metabolism in skin cells is not fully elucidated.
Purpose of the Study:
- To identify steroid-metabolizing enzymes in cultured human epidermal keratinocytes.
- To characterize the activity and kinetics of these enzymes.
- To understand the biotransformation pathways of various steroids in keratinocytes.
Main Methods:
- Incubation of cultured human epidermal keratinocytes with radiolabeled steroids.
- Analysis of steroid metabolites using chromatographic techniques.
- Enzyme activity assays for sulfatase, 17 beta-HSOR, 3 alpha-HSOR, 3 beta-HSOR, and 5 alpha-reductase.
Main Results:
- Keratinocytes exhibit sulfatase activity, converting E1S to E1 and DS to DHEA.
- 17 beta-HSOR activity was confirmed, with higher specific activity in long-term cultured cells.
- Multiple enzymes including steroid 5 alpha-reductase and hydroxysteroid oxidoreductases were identified, indicating significant steroid biotransformation capacity.
Conclusions:
- Human epidermal keratinocytes possess a broad spectrum of steroid-metabolizing enzymes.
- These enzymes facilitate the biotransformation of various androgens and estrogens.
- The findings suggest an intrinsic role for keratinocytes in regulating steroid levels within the skin.