LC-MS analyses of steroid hormones or their metabolites from faeces and urine: Problems and perspectives

Deschner T

Department of Primatology; Max-Planck-Institute for Evolutionary Anthropology, Leipzig, e-mail: deschner@eva.mpg.de

Within the last decades, measuring steroid hormones in non-invasively collected samples such as urine or faeces has become a powerful tool providing important information about an animal’s endocrine status.  Group specific immunoassays have been developed and checklists created to assure a proper validation of specific assays for different species and matrices. Validations often necessitate invasive experiments such as challenge studies or the administration of radioactively labeled hormones to assure that measurements achieved with the assay correspond to the hormone of interest. Such validations are problematic for use on endangered species where invasive administration of hormones is not allowed. Here a comparison of measured values in immunoassays with the ones in LC-MS/MS can be helpful, to explore if it is indeed the targeted hormones or their metabolites that are responsible for the variation observed in the measures received with immunoassays. Furthermore, LC-MS/MS measurements can be of major interest when a simultaneous quantification of a high number of steroids is needed, for example for the monitoring of cross-talk between the gonadal and the adrenal axis. Here we present an overview of general principles of LC-MS/MS measurements, considerations for sample extraction and examples of recent applications. We furthermore give estimates of the costs for the purchase, maintenance of LC-MS/MS systems and of sample measurements.