IGFBP1 and hyperinsulinism: Hyperinsulinemia causes hyperandrogenism through elevation of sex hormone free fractions due to decreased SHBG (sexual hormone binding globulin), increased hepatic insulin-like growth factor-1 (IGF-1) production, and/or increased IGF-1 bioavailability through a reduction in IGFBP-1 generation [17,63].