ACHE and polycystic ovary syndrome: Currently, activity of acetylcholine esterase (AChE), a hydrolytic enzyme of acetylcholine, was found elevated in the hypothalamus and pituitary of PCOS rats along with decreased expression of M2 muscarinic acetylcholine receptor (M2AChR), thus, suggesting reduced levels of acetylcholine in PCOS condition which may contribute to increased GnRH and LH pulse frequency in PCOS women.