“…The analytical sensitivity of LH and FSH assays were 0.1 mUI/mL and 0.1 mUI/mL, respectively, and intra-assays of LH and FSH were 6.5% and abnormality but does display metabolic features of PCOS [10]. However, the rat model induced by letrozole, a non-steroidal aromatase inhibitor, shows elevated LH and T levels, anovulation, absence of corpus luteum, hyperplasia of the theca cell layer, diminished granulosa cells and increased ovarian size, which are similar findings to human PCOS [11][12][13]. Therefore, the letrozole-induced PCOS model rat may be suitable for study of the mechanism of anovulation, including hypersecretion of LH originated from the hypothalamus, which cannot be tested in the hypothalamus of human PCOS.…”