Inositols in Polycystic Ovary Syndrome: An Overview on the Advances

Myo-inositol (MI) and d-chiro-inositol (DCI) are two stereoisomers of inositol. These natural molecules are safe and well-tolerable and have insulin-sensitizing activity. In addition, MI mediates FSH signaling. MI and DCI are dietary supplements with proven therapeutic activity in polycystic ovary syndrome (PCOS). New preclinical and clinical studies support the importance of administering a combination of MI and DCI in the 40:1 ratio. Of note, this is the physiologic ratio in blood. Inositol absorption at intestinal level and its therapeutic effect in PCOS are significantly improved with the coadministration of alpha-lactalbumin. In conclusion, inositols represent an important therapeutic advance for PCOS treatment. This review details the physiologic roles of two insulin sensitizers, myo-inositol (MI) and d-chiro-inositol (DCI). In the human ovary, MI is a second messenger of follicle-stimulating hormone (FSH) and DCI is an aromatase inhibitor. These activities allow a treatment for polycystic ovary syndrome (PCOS) to be defined based on the combined administration of MI and DCI, where the best MI:DCI ratio is 40:1. Moreover, MI enhances the effect of metformin and clomiphene on the fertility of PCOS women seeking pregnancy. As impaired intestinal transport may lead to unsuccessful inositol treatment, we also discuss new data on the use of alpha-lactalbumin to boost inositol absorption. Overall, the physiological activities of MI and DCI dictate the dosages and timing of inositol supplementation in the treatment of PCOS. This review details the physiologic roles of two insulin sensitizers, myo-inositol (MI) and d-chiro-inositol (DCI). In the human ovary, MI is a second messenger of follicle-stimulating hormone (FSH) and DCI is an aromatase inhibitor. These activities allow a treatment for polycystic ovary syndrome (PCOS) to be defined based on the combined administration of MI and DCI, where the best MI:DCI ratio is 40:1. Moreover, MI enhances the effect of metformin and clomiphene on the fertility of PCOS women seeking pregnancy. As impaired intestinal transport may lead to unsuccessful inositol treatment, we also discuss new data on the use of alpha-lactalbumin to boost inositol absorption. Overall, the physiological activities of MI and DCI dictate the dosages and timing of inositol supplementation in the treatment of PCOS. a whey protein that may work also as a ‘carrier’ for metal ions (mainly divalent, such as Ca2+ and Fe2+) and for vitamin D. In more general terms, α-LA seems to be a facilitator of passage through biological barriers. Androgens (mainly, testosterone, dihydrotestosterone, dehydroepiandrosterone, dehydroepiandrosterone sulfate, androstenedione, and androstenediol); steroid hormones, produced by testis, ovary, and adrenal gland. a glycoprotein hormone synthesized by follicle granulosa cells of the preantral and small antral follicles. It regulates their sensitivity to FSH and subsequent recruitment in the ovarian cycle. an enzyme involved in the conversion of androgens to estrogens. The inhibition of its activity increases the levels of testosterone and other androgens. (gonadotropin), a glycoprotein, which supports and controls the growth and development of ovarian follicles. It stimulates estrogen production by granulosa cells. an endocrine disorder, due to an excess of androgens in females, that causes hirsutism, acne after adolescence, alopecia, and deepening of voice. a technique that involves extracorporeal fertilization of gametes by co-incubation of oocytes with sperm in vitro. second messengers released by heterotrimeric G protein-regulated hydrolysis (phospholipase-mediated) of membrane phosphatidylinositols. a peptide hormone produced by β cells of pancreatic islets. Insulin resistance means that cells have a reduced response to insulin. (gonadotropin), a glycoprotein, which stimulates ovulation and the subsequent development of the corpus luteum. In the follicle thecal cells, LH induces androgen synthesis, then, in granulosa cells, androgens are precursor of estrogens. this ratio (in mIU/ml) is higher in PCOS patients (above 2:1). Normally, women show about equal amounts of LH and FSH during the early part of their cycle, with a short temporary period of LH surge. Instead, many women with PCOS have their LH levels two or three times higher than the FSH levels.