Endocrine Abstracts

1,25-dihydroxyvitamin D3, the hormonally active metabolite of vitamin D3, tightly controls calcium blood levels. An increase of 1,25-dihydroxyvitamin D3 leads to an increase in calcium concentration with calcium originating from various resources, including bone tissue. To assess a patient’s vitamin D status the precursor metabolite 25-hydroxyvitamin D3 is determined. However, measurement of 1,25-dihydroxyvitamin D is required w...

The adrenal and gonadal androgens testosterone, androstenedione and dehydroepiandrosterone (DHEA) play an important role in sexual development and fertility as well as in several other processes. We developed a method to assess serum testosterone, androstenedione and DHEA levels in one run using isotope-dilution liquid-chromatography tandem mass spectrometry (ID-LC-MS/MS). Sample preparation consisted of addition of internal standards (13C3-testosterone, ...

Recently, liquid chromatography–tandem mass spectrometry (LC–MS/MS) was stated to be the method of choice to measure sex steroids.1 Information on the mutual agreement of LC–MS/MS methods, however, is scarce. Therefore, we compared seven published LC–MS/MS methods for the simultaneous measurement of testosterone, androstenedione, and DHEA. Fifty-five random serum samples obtained from volunteers were analysed in duplicate by seven published LC&#1...