GNRH1 and Insulin resistance: PCOS: Polycystic Ovary Syndrome; MetS: Metabolic Syndrome; HOMA-IR: Homeostatic Model Assessment for Insulin Resistance; QUICKI: Quantitative Insulin Sensitivity Check Index; LH: Luteinizing Hormone; FSH: Follicle-Stimulating Hormone; GnRH: Gonadotropin-Releasing Hormone; AUC: Area Under the Curve; IVF: In Vitro Fertilization; s.c.: Subcutaneous; OHSS: Ovarian Hyperstimulation Syndrome; SHBG: Sex Hormone-Binding Globulin