This low efficiency or incompleteness may be important in inducing T cell anergy. Previous studies demonstrated that manipulations/modifications in the early stage of T cell activation led to the induction of T cell anergy. Therefore, the slight induction of the activation marker by 20-2b2 was a Coptisine-chloride ributed to an incomplete activation process in the early stage of T cell activation, and may result in the induction of T cell anergy. The molecular mechanisms by which 20-2b2 induces T cell anergy need to be investigated in more detail. Hyperandrogenism is a cardinal feature of polycystic ovary syndrome. Both ovarian and adrenal androgen sources contribute to serum androgen levels. The increased androgen production of the theca cells in the ovary has been well established. In addition, there is some evidence for increased adrenal steroidogenesis compared to controls. However, our own data do not demonstrate elevation of DHEAS, an adrenal specific androgen, in women with PCOS. Thus, the importance of the adrenal contribution to androgen secretion remains to be determined. Despite the importance of accurate androgen measurements in PCOS, most of the clinically available androgen immunoassays have problems with sensitivity, specificity and accuracy. The difficulties are exemplified by direct immunoassays and extractiononly radioimmunoassays for testosterone, which perform well for testosterone levels in the range of healthy, young men but do not have sufficient sensitivity and accuracy at the concentrations found in women and children. However, some investigators have demonstrated that RIA can perform as well as LC-MS/MS. In addition to improved accuracy and sensitivity for Procyanidin-B1 steroid measurements, liquid chromatographytandem mass spectrometry can separate compounds and can therefore be used to measure multiple steroids from one sample. The current study examines a new LC-MS/MS for the simultaneous determination of 13 steroids. The testosterone, androstenedione, progesterone and 17-hydroxyprogesterone measurements were compared to those determined using radioimmunoassays and immunoassays. The simultaneous measurement of 13 steroid hormones using LC-MS/MS was then used to evaluate ovarian and adrenal steroids in women with PCOS and to estimate the relative steroid enzyme activity in women with PCOS compared to controls. The study demonstrates the development of a LC-MS/MS that can measure multiple adrenal and gonadal steroids simultaneously. The data demonstrate that LC-MS/MS testosterone, androstenedione, progesterone and 17-hydroxyprogesterone levels are lower than those measured using RIAs. Using LC-MS/MS to measure steroid levels from the adrenals and ovaries simultaneously, women with PCOS have higher testosterone, androstenedione and 17OH progesterone levels, but no difference in predominantly adrenal steroids. While not a measure of enzyme activity, the product-to-precursor ratios point to the possibility that 3b-hydroxysteroid dehydrogenase has increased activity in women with PCOS. These pa erns of increased androgens measured simultaneously are consistent with an ovarian source of androgen production in women with PCOS, with direct testing needed. Comparing RIAs and immunoassays with LC-MS/MS for four steroids, it was clear that the RIAs read consistently higher compared to the LC-MS/MS.