2.4. Serum Hormone Analysis

Blood samples were collected directly from the inferior vena cava with a 1-mL syringe at the end of the experiment. Serum was obtained by centrifugation at 13,000 rpm for 15 min and stored at −70 °C until use. Serum luteinizing hormone (LH) levels were measured using LH ELISA kit (Enzo Life Science, Inc., Farmingdale, NY, USA). Serum follicle-stimulating hormone (FSH) levels were measured using an FSH ELISA kit (Enzo Life Science, Inc., Farmingdale, NY, USA). Serum 17β-Estradiol levels were measured using a 17β-Estradiol ELISA kit (Enzo Life Science, Inc., Farmingdale, NY, USA). Serum testosterone levels were measured using a testosterone ELISA kit (Enzo Life Science, Inc., Farmingdale, NY, USA). All kits were used according to the manufacturer’s instructions, and each sample was analyzed in duplicate.