Chapter 9: The Reproductive System

The Reproductive System details how pulsatile gonadotrophin-releasing hormone (GnRH) from the hypothalamus triggers the anterior pituitary to secrete luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which subsequently regulate steroidogenesis and gametogenesis in the ovaries and testes. The text examines the metabolic pathways of sex steroids like oestradiol, progesterone, and testosterone, highlighting the role of sex-hormone-binding globulin (SHBG) in modulating their biological activity. A significant portion of the material is dedicated to reproductive disorders, including the biochemical diagnosis of hyperprolactinaemia, polycystic ovary syndrome (PCOS), and various forms of hypogonadism—differentiating between primary hypergonadotrophic and secondary hypogonadotrophic states. Furthermore, it addresses clinical presentations like amenorrhoea, hirsutism, and virilism, while providing insights into sexual differentiation from conception through puberty. Diagnostic protocols such as GnRH and hCG stimulation tests are analyzed for their utility in assessing pituitary and gonadal function, offering a comprehensive study guide for understanding metabolic medicine as it pertains to reproductive health and hormonal imbalances.