Testosterone metabolism in an in vitro skin model

Area of Science:

• Dermatology
• Pharmacology
• Biotechnology

Background:

• Skin's metabolic activity is crucial for topical compound penetration.
• Current methods use animal or cadaver skin, presenting ethical and practical limitations.
• A reliable in vitro model is needed to study skin metabolism and penetration.

Purpose of the Study:

• To characterize testosterone metabolism and penetration using a novel 3D human skin model.
• To assess the model's suitability as an alternative to animal or cadaver skin.
• To identify key metabolites and metabolic pathways involved in testosterone transformation.

Main Methods:

• A 3D human skin model composed of keratinocytes and fibroblasts was utilized.
• Radiolabeled testosterone ([3H]testosterone) penetration was measured at different temperatures (32°C vs. 4°C).
• Metabolites were identified using High-Performance Thin-Layer Chromatography (HPTLC) and autoradiography after incubation with the skin model.

Main Results:

• Testosterone penetration was temperature-dependent, suggesting metabolic influence.
• The 3D model metabolized testosterone into polar and non-polar compounds, mirroring neonatal foreskin metabolism.
• Fibroblasts and keratinocytes both contributed to testosterone metabolism; dihydrotestosterone and androstane-3,17-diol were identified as keratinocyte-specific metabolites, inhibited by metyrapone.

Conclusions:

• The developed 3D human skin model is a reproducible and metabolically active system.
• This model serves as a valuable alternative to animal or cadaver skin for skin penetration research.
• The model effectively elucidates the role of skin metabolism in the penetration of topically applied substances.