https://www.selleckchem.com/products/pqr309-bimiralisib.html The method was applied to the analysis of steroid hormone levels in adult female whisker segments obtained from southern elephant seals (Mirounga leonina), n = 10, and two fur seal species, Antarctic fur seals (Arctocephalus gazella; n = 5) and subantarctic fur seals (Arctocephalus tropicalis; n = 5), sampled between 2012 and 2017. In the whisker subsamples analyzed (n = 71), the median concentration of steroid hormones detected above the LOQ ranged from 2.0 to 273.7 pg/mg. This was the first extraction of multiple C19 and C21 steroids, including their C11-oxy metabolites, from the whiskers of mammals. Measuring hormones sequentially along the whisker lengths can contribute to our understanding of the impact of stress associated with environmental/climate changes that affect the health, survival of organisms, as well as to delineate the reproductive cycles of free-living mammals with cryptic life stages. The standard approach to detect misuse with testosterone in sport is based on the determination and evaluation of the urinary steroid profile followed by the confirmation of atypical profiles using isotope ratio mass spectrometry. The detection capacity of these methods can be attenuated by confounding factors or testosterone preparations with endogenous isotopic fingerprints. An alternative detection method for misuse of an endogenous steroid in sports is the direct detection of the administered steroid ester present in most preparations. Thus unambiguous proof for doping misuse can be delivered. In this work, the sensitivity of gas chromatography coupled to a triple quadrupole with chemical ionization (GC-CI-MS/MS) is applied to detect trace levels of 10 testosterone and 2 nandrolone esters in plasma for in human doping analysis. The detection method was developed employing a liquid-liquid extraction and HPLC cleanup step before analysis on the GC-CI-MS/MS. The quantitative method was validated in a line