Physiology, Somatostatin

Excerpt

Somatostatin is a cyclic peptide well known for its strong regulatory effects throughout the body. Also known by the name of growth hormone inhibiting hormone, it is produced in many locations, which include the gastrointestinal (GI) tract, pancreas, hypothalamus, and central nervous system (CNS). Two active forms of the peptide exist, and they vary in length at fourteen amino acids and twenty-eight amino acids respectively. The two isoforms have considerable overlap in activity and differ primarily in their location of effect. The shorter isoform (14 amino acids) works primarily in the brain, while the longer (28 amino acids) form operates in the GI tract. Its half-life is between 1 to 3 minutes.

Somatostatin produces predominantly neuroendocrine inhibitory effects across multiple systems. It is known to inhibit GI, endocrine, exocrine, pancreatic, and pituitary secretions, as well as modify neurotransmission and memory formation in the CNS. It also prevents angiogenesis and has anti-proliferative effects on healthy and cancerous cells in human and animal models.

Due to its short half-life, somatostatin has been formulated exogenously in much more stable forms with a longer half-life; this allows for its primary clinical use, which is the treatment of neuroendocrine tumors (NET).