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, ...

Pre-autonomic neurons in the hypothalamic paraventricular nucleus (PVN) project to sympathetic and parasympathetic motor nuclei in the brain stem, from where the liver and white adipose tissue (WAT) are innervated by both branches of the autonomic nervous system (ANS). Studies by our group and by others have shown that these neural pathways modulate glucose and lipid metabolism in liver and WAT. Given the abundant thyroid hormone receptor (TR) expression in the PVN we hypothes...

Background: LC-MS/MS is recommended for accurately measuring circulating steroids. However, laboratories using LC-MS/MS adopt various pre-analytical and analytical strategies, and little is known about comparability of results. Whether different blood derivatives impact LC-MS/MS measurements is unclear, and the benefit of unifying the calibration system among laboratories was not tested.Aim: Comparisons of LC-MS/MS measurements of circulating aldosterone...