The pituitary gland is a small, oval gland lying at the base of the brain. It is divided into two sections, anterior and posterior.

The anterior pituitary is a collection of cells that produce hormones, including thyroid-stimulating hormone (TSH), adrenocorticotrophic hormone (ACTH), follicle stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), and growth hormone (GH). The release of the hormones by these cells is controlled by the hypothalamus.

The posterior pituitary is made up of around 50,000 nerve endings and produced anti-diuretic hormone (ADH) and oxytocin. These nerves release their hormones straight into the blood.