The feasibility of quantitative analysis of androgen metabolism by use of single dermal papillae from human hair follicles.
Androgenetic alopecia (AGA) is a dihydrotestosterone-mediated process, characterized by continuous miniaturization of androgen sensitive hair follicles (HF). Although increased 5 alpha-reductase (5aR) activity in affected HF is a key feature in the pathogenesis of AGA, only little is known about the in vivo expression of 5aR within AGA-affected HF. Recent studies have shown that the dermal papilla (DP) is the predominant site of type 2 5aR expression within the human HF, but direct measurements of 5aR activity in intact DP of AGA-affected HF have not been reported so far, mainly because of technical problems. Hence there is a need for a reliable and sensitive method of measuring 5aR activity in fresh tissues. As a novel approach, we used freshly isolated, intact DP and a highly sensitive HPLC-radiomatic flow scintillation system to measure 5aR. In this way we were able to measure 5aR even in small DPs from miniaturized HF. Our results show that DP from the occipital scalp express ex vivo considerable amounts of 5aR activity, but the measurable enzyme activities of individual DP differ considerably. Therefore the use of only one or two DP is at present not a reliable tool to analyze 5aR activity ex vivo.
Department of Dermatology, Philipp University, Marburg, Germany. niiyama@mailer.uni-marburg.de
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Niiyama
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Happle
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Hoffmann
D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase / Q000032:analysis*; D000505:Alopecia / Q000378:metabolism*; D000728:Androgens / Q000032:analysis / Q000378:metabolism*; D001706:Biopsy; D005240:Feasibility Studies; D005260:Female; D018859:Hair Follicle / Q000378:metabolism*; D006801:Humans; D008297:Male; D012535:Scalp / Q000473:pathology*; D012680:Sensitivity and Specificity
D000728:Androgens; D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase