The assessment of paired samples showed that NPY concentration follicular fluid was higher than serum (mean ± SD; all women (n = 33), 20.1 ± 6.4 vs. 14.0 ± 3.7 pg/ml, p < 0.001; non-PCOS subjects (n = 23), 19.7 ± 6.3 vs. 14.1 ± 3.6, p < 0.001; PCOS subjects (n = 10), 20.9 ± 6.8 vs. 14.0 ± 4.3, p < 0.01). The gene discussed is NPY; the disease is polycystic ovary syndrome.