Pituitary Gland

The pituitary gland, located at the base of the brain, is the central coordinator of the reproductive hormonal cascade. In response to GnRH pulses from the hypothalamus, the anterior pituitary releases FSH (follicle-stimulating hormone) and LH (luteinizing hormone), which act directly on the ovaries and testes.

The pituitary also secretes prolactin (stimulating milk production), TSH (regulating the thyroid), growth hormone, and ACTH. Pituitary disorders — including prolactinoma (benign tumor), Sheehan syndrome (postpartum pituitary infarction), and hypopituitarism — can profoundly disrupt the hormonal axis and cause infertility.

Medications used in IVF (GnRH agonists and antagonists) work by suppressing or modulating pituitary output of LH and FSH.