text: Different mechanisms explaining why metformin therapy would facilitate ovulation induction by CC in CC-resistant PCOS patients have been proposed, including an intrinsic alteration of follicle steroidogenesis through the insulin-libe growth factor-I (IGF-I) pathway in granulosa cells,(8) direct inhibition of androgen production in ovarian thecal cells,(23) reduction in the adrenal steroidogenesis response to adrenocorticotropic hormone (ACTH),(24) and, more recently, metformin’s central action on the pituitary gland, with LH lowering and prolactin effects in women with PCOS.(25)