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Published on: May 5, 2022
Regional Differences in Human Intestinal Drug Metabolism
Raditya Iswandana1, Marina I Irianti1, Dorenda Oosterhuis1
1Division of Pharmaceutical Technology and Biopharmacy (R.I., M.I.I., D.O., H.A.M.M., P.O.) and Division of Pharmacokinetics, Toxicology and Targeting (M.T.M., M.H.d.J.), Department of Pharmacy, University of Groningen, Groningen, The Netherlands; Faculty of Pharmacy, Universitas Indonesia, Depok, Indonesia (R.I.); Department of Surgery, University Medical Center Groningen, Groningen, The Netherlands (H.S.H.); and Department of Clinical Medicine, Aarhus University, Aarhus, Denmark (H.A.M.M.).
Human intestines show distinct drug metabolism patterns. Phase I metabolism is concentrated in the ileum, while Phase II metabolism occurs mainly in the colon, with some sex-based variations observed.
Area of Science:
- Pharmacology
- Gastroenterology
- Drug Metabolism
Background:
- The intestines play a crucial role in nutrient/water absorption and drug metabolism.
- Significant regional variations in drug-metabolizing enzymes exist along the human intestinal tract.
- Limited research has explored these regional differences in human intestinal drug metabolism.
Purpose of the Study:
- To evaluate regional differences in Phase I and Phase II drug metabolism in the human ileum and colon.
- To investigate the utility of precision-cut intestinal slices (PCIS) for studying intestinal drug metabolism.
Main Methods:
- Human ileum and colon PCIS were incubated with testosterone (Phase I) and 7-hydroxycoumarin (7-HC) (Phase II).
- Metabolite formation was quantified using high-performance liquid chromatography (HPLC).
Main Results:
- Phase I metabolism predominantly yielded androstenedione, 6β-hydroxytestosterone, and 2β-hydroxytestosterone in the ileum.
- Phase II metabolism predominantly yielded 7-HC sulfate in the ileum and 7-HC glucuronide in the colon.
- Sex differences were observed, with higher Phase II metabolite formation in men compared to women.
Conclusions:
- Phase I drug metabolism is primarily located in the ileum, while Phase II metabolism is mainly in the colon.
- Human PCIS are a viable model for investigating regional and sex-specific differences in intestinal drug metabolism.
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