Octreotide

Leuprolide (brand name Lupron) is a synthetic GnRH agonist, a modified peptide far more potent than natural GnRH, and it is FDA-approved for advanced prostate cancer, endometriosis, uterine fibroids, and central precocious puberty. The clever part is counterintuitive: it works by overstimulating the GnRH system so hard that the pituitary shuts down sex hormone production. It is a real, long-established prescription drug (first US approval 1985), not a research peptide, and it carries meaningful side effects from the low-hormone state it creates.

Lanreotide (development code BIM-23014) is an eight-amino-acid somatostatin analog, a close cousin of octreotide, given as a long-acting deep-injection gel (Somatuline Depot/Autogel) usually once a month. The FDA approved it for acromegaly in 2007, for gastroenteropancreatic neuroendocrine tumors in 2014, and for carcinoid syndrome in 2017. Generic versions now exist alongside Ipsen's Somatuline Depot. It is established prescription medicine, not an experimental compound.

Pasireotide (brand name Signifor) is a second-generation somatostatin analog, a cyclic six-amino-acid peptide engineered to hit more receptor subtypes than octreotide or lanreotide. Its standout use is Cushing's disease, where it was the first drug FDA-approved (2012) to directly target the pituitary tumor driving cortisol excess, and it is also approved for acromegaly that resists first-line analogs. The catch is real and well known: it raises blood sugar in most patients, so it is a powerful but high-maintenance option.

Pegvisomant (brand name Somavert) flips the usual acromegaly strategy on its head: instead of telling the tumor to make less growth hormone, it blocks growth hormone's receptor on target tissues directly. It is a PEGylated, genetically modified version of human growth hormone that acts as a receptor antagonist, FDA-approved in 2003 for acromegaly patients who do not respond well to surgery or other drugs. It is the single most effective option for normalizing IGF-1, which is why it is a key second-line therapy.

Insulin is the body's main blood-sugar-lowering hormone, a 51-amino-acid protein made of two chains (a 21-residue A-chain and a 30-residue B-chain) held together by disulfide bonds. Secreted by the beta cells of the pancreas, it tells the liver, muscle, and fat to take up glucose and store energy. Discovered in 1921 and first given to a patient in January 1922, it remains one of the most consequential drugs in medicine and is the cornerstone of treatment for type 1 and many cases of type 2 diabetes.

Glucagon is insulin's counterweight, a 29-amino-acid peptide hormone secreted by the alpha cells of the pancreas that raises blood sugar instead of lowering it. When glucose drops, glucagon tells the liver to break down stored glycogen and make new glucose, pushing blood sugar back up. Medically it is the emergency rescue treatment for severe hypoglycemia (the kind that knocks out a person with diabetes), available as injectable kits and a nasal-spray form, and it is also used in some diagnostic imaging to relax the gut.