Untitled

Abstract

24Steroids play multiple roles in the regulation of development, physiology, reproduction, and 25 behavior. Measuring circulating steroids is especially challenging since concentrations are 26 extremely labile, responding to stressors within minutes. Matrices that integrate long-term 27 steroid levels are therefore valuable as biomarkers of baseline, as well as chronic steroid 28 exposures. Here we report on a simple method to extract and measure accumulated 29 testosterone from human fingernails using commercial EIA kits. Further, we demonstrate 30 known human testosterone sex and age trends. Thus, this method is a potential tool for 31 biomonitoring endogenous as well as exogenous steroid exposure. 32 33