EIF2AK3 and polycystic ovary syndrome: As shown in Fig. 5E–G, phospho-IRE1 and phospho-PERK protein expression and XBP1(S) mRNA expression in granulosa cells of PCOS mice was reduced by treatment with TUDCA or BGP-15, suggesting that administration of these inhibitors decreased ER stress in granulosa cells of PCOS mice.