Tissuelyzer lt homogenizer

Tumor samples were homogenized in sterile water using a Tissuelyzer LT homogenizer (Qiagen, Venlo, the Netherlands), and the concentrations of androstenedione, testosterone (T), and DHT were measured from the tumor homogenates and serum samples using gas chromatographyetandem mass spectrometry. 18 The lower limits of quantitation (LLOQs) for androstenedione, T, and DHT in mouse serum samples were 12, 8, and 2.5 pg/mL, respectively. The concentrations of pregnenolone and progesterone were measured in the tumor homogenates and serum samples using liquid chromatographyetandem mass spectrometry. 19 The LLOQs for pregnenolone and progesterone in serum samples were 10.4 and 10.7 pg/mL, respectively. The concentrations of 3a-androstanediol (3adiol) and 3b-androstanediol (3b-diol) were measured in the tumor homogenates using liquid chromatographyetandem mass spectrometry; the lower limit of detection (LLOD) for 3a-and 3b-diol was 400 pg/mL. 20 The LLOQ was used for statistical analysis if steroid concentrations in samples were lower than the quantitation limit. One gram of tumor sample was considered equivalent to 1 mL of serum to compare intratumoral steroid levels with serum steroid levels.