The Hypothalamus
The hypothalamus is located in the brain, between the cerebrum and the brain stem, and connects to the pituitary gland, which aids in transporting neurohormones from the anterior and posterior lobes of the pituitary gland (Timby & Smith, 2013). The hypothalamus influences the release of hormones from the pituitary lobes. Six hormones are secreted by the hypothalamus:
- Thyrotropin-releasing hormone (TRH) which is responsible for stimulating the release of thyroid-stimulating hormone (TSH) from the anterior pituitary gland.
- Corticotropin-releasing hormone (CRH), causes anterior pituitary gland to secrete adrenocorticotropic hormone (ACTH).
- Gonadotropin-releasing hormone (GnRH), responsible for triggering the sexual development at onset of puberty and continues on to stimulate anterior pituitary gland to secret luteinizing hormone (LH) and follicle-stimulating hormone (FSH).
- Growth hormone-releasing hormone (GHRH) helps to release of somatotropin (growth hormone [GH]) from anterior pituitary gland. Secretion of GHRH is also controlled by another hormone produced in hypothalamus, Somatostatin.
- Somatostatin inhibits GHRH and TSH. Blocks secretion of gastrin, cholecystokinin, and secretin- gastrointestinal hormones. Is also responsible for lowering blood flow within the intestine; suppresses the release of insulin and glucagon from the pancreas; and also suppresses release of exocrine enzymes from the pancreas (Timby & Smith, 2013, p. 750).
- Hypothalamic dopamine prevents the release of prolactin from the anterior pituitary. Note that there are various forms of dopamine secreted throughout the body, five in fact.
Review the rest of the Endocrine system hormones on page 748-750 of your text.