PCOS and Insulin: Why It Matters

PCOS and Insulin Resistance

Polycystic ovary syndrome, or PCOS, is characterized by hormonal abnormalities due to endocrine gland disruptions.  Endocrine glands are involved in the secretion of hormones that regulate all functions in the body. When these abnormalities occur, it can lead to menstrual irregularities, reduce ovulation rate and fertility, and is associated with insulin resistance (1). 

What is Insulin Resistance? What is Hyperinsulinemia? Why Does it Matter?

Insulin is an essential hormone that is used to regulate blood sugars, or glucose, and helps store away glucose for later use when needed for energy.  Alterations in circulating insulin levels, and the cell’s responsiveness to insulin can have a cascading affect in the regulation and expression of other hormones.  Many of these hormones are involved in the etiology of PCOS symptoms.   

Insulin Resistance is defined by a cell or tissue’s, reduced responsiveness to the amount of insulin it is being exposed to (2).  Insulin Resistance makes it more difficult for the body to properly manage blood sugar levels. Hyperinsulinemia occurs when your pancreas creates more insulin than what is needed.  Hyperinsulinemia often occurs due to insulin resistance in an attempt to regulate glucose levels.

There is still evolving research surrounding insulin resistance and PCOS.  But current research suggests insulin resistance is inherently present for those with PCOS.  A Cureus review article published in 2022 reported that there is a defect in insulin reactivity in metabolically active tissue, including skeletal muscle (3). 

Insulin and Reproductive Hormones

Insulin is also considered a co-gonadotropin. Gonadotropins are hormones that help regulate ovarian and testicular function, and general reproductive regulation (4).

As insulin levels increase, the amount of sex hormone-binding globulin (SHBG) decreases.  As this occurs free androgens, or sex hormones, become more present (3). The most common androgen is testosterone for both male and females.  Some women with PCOS are noted to have higher levels of testosterone due to insulin resistance.  They are also noted to have increased Luteinizing Hormone that increases testosterone production in the ovaries. This can lead to excess hair growth, infertility, irregular menstrual cycles, acne, and weight gain, as well as other unwanted PCOS symptoms.

Research has shown that managing blood glucose levels through diet and exercise can reduce further exacerbation of insulin dysregulation, and may improve PCOS symptoms, including infertility (3).

Sources:

1. MA, Salomone S, Carruba MO, Drago F. Polycystic Ovary Syndrome: Insights into the Therapeutic Approach with Inositols. Front Pharmacol. 2017;8:341. Published 2017 Jun 8. doi:10.3389/fphar.2017.00341

2. Michael H. Shanik, Yuping Xu, Jan Škrha, Rachel Dankner, Yehiel Zick, Jesse Roth; Insulin Resistance and Hyperinsulinemia: Is hyperinsulinemia the cart or the horse?. Diabetes Care 1 February 2008; 31 (Supplement_2): S262–S268. https://doi.org/10.2337/dc08-s264

3. Purwar A, Nagpure S. Insulin Resistance in Polycystic Ovarian Syndrome. Cureus. 2022 Oct 16;14(10):e30351. doi: 10.7759/cureus.30351. PMID: 36407241; PMCID: PMC9665922.

4. Diamanti-Kandarakis E, Dunaif A. Insulin resistance and the polycystic ovary syndrome revisited: an update on mechanisms and implications. Endocr Rev. 2012;33(6):981-1030. doi:10.1210/er.2011-1034