Terlipressin (Glypressin) is indicated for the treatment of bleeding oesophageal varices and in some countries for the treatment of hepato-renal syndrome type 1. It is a prodrug and is converted to the lysine vasopressin in the circulation after the N-triglycyl residue is cleaved by endothelial peptidases. This results in a ‘slow release’ of the vasoactive lysine vasopressin. Terlipressin exerts its action by activating V1a, V1b and V2 vasopressin receptors.

Linaclotide (marketed under the trade name Linzess and Constella) is a peptide agonist of the guanylate cyclase 2C (GC-C). Once linaclotide and its active metabolite binds to GC-C, it has local effect on the luminal surface of the intestinal epithelium. Activation of GC-C by linaclotide results in the intra- and extracellular increase of cyclic guanosine monophosphate concentrations (cGMP). This elevation of cGMP levels stimulates the secretion of chloride and bicarbonate into the intestinal lumen via activation of cystic fibrosis transmembrane conductance regulator (CFTR) ion channel. The metabolite of linaclotide MM-419447 (CCEYCCNPACTGC) contributes to the pharmacologic effects of linaclotide. Ultimately, linaclotide helps patients with IBS (especially with constipation) as GI transit is accelerated and the release of intestinal fluid is increased. In animal models, a decrease in visceral pain after administration of linaclotide may be observed. A decrease in the activity of pain-sensing nerves occurs as a result of an increase in extracellular cGMP. It was approved by the FDA in August 2012 for the treatment of chronic idiopathic constipation and irritable bowel syndrome with constipation (IBS-C) in adults.

Tesamorelin is an analog of human growth hormone-releasing factor (GRF). The peptide precursor of tesamorelin acetate is produced synthetically and is comprised of the 44 amino acid sequence of human GRF. In vitro, tesamorelin binds and stimulates human GRF receptors with similar potency as the endogenous GRF. GRF, also known as growth hormone-releasing hormone (GHRH), is a hypothalamic peptide that acts on the pituitary somatotroph cells to stimulate the synthesis and pulsatile release of endogenous growth hormone (GH), which is both anabolic and lipolytic. GH exerts its effects by interacting with specific receptors on a variety of target cells, including chondrocytes, osteoblasts, myocytes, hepatocytes, and adipocytes, resulting in a host of pharmacodynamic effects. Some, but not all these effects, are primarily mediated by IGF-1 produced in the liver and in peripheral tissues. Tesamorelin is the first and, so far, only treatment indicated for the reduction of excess abdominal fat in patients with HIV-associated lipodystrophy. Tesamorelin is effective in improving visceral adiposity and body image in patients with HIV-associated lipodystrophy over 26-52 weeks of treatment. Potential limitations for its use include high cost and lack of long-term safety and adherence data. Tesamorelin provides a useful treatment option for management of patients with significant lipodystrophy related to HIV infection.

Lanreotide is a medication used in the management of acromegaly and symptoms caused by neuroendocrine tumors, most notably carcinoid syndrome. It is a long-acting analog of somatostatin. It is available in several countries, including the United Kingdom, Australia and Canada, and was approved for sale in the United States by the Food and Drug Administration on August 30, 2007. Lanreotide was developed in the lab of Dr. David H. Coy, School of Medicine. Dr. Coy serves as Director of the Peptide Laboratory. Lanreotide (as lanreotide acetate) is manufactured by Ipsen, and marketed under the trade name Somatuline. The mechanism of action of lanreotide is believed to be similar to that of natural somatostatin. Lanreotide has a high affinity for human somatostatin receptors (SSTR) 2 and 5 and a reduced binding affinity for human SSTR1, 3, and 4. Activity at human SSTR 2 and 5 is the primary mechanism believed responsible for GH inhibition. Like somatostatin, lanreotide is an inhibitor of various endocrine, neuroendocrine, exocrine and paracrine functions. Lanreotide inhibits the basal secretion of motilin, gastric inhibitory peptide and pancreatic polypeptide, but has no significant effect on the secretion of secretin. Lanreotide inhibits postprandial secretion of pancreatic polypeptide, gastrin and cholecystokinin (CCK). In healthy subjects, lanreotide produces a reduction and a delay in post-prandial insulin secretion, resulting in transient, mild glucose intolerance.

Triptorelin is a synthetic decapeptide agonist analog of luteinizing hormone releasing hormone (LHRH). It works by decreasing the production of certain hormones, which reduces testosterone levels in the body. Animal studies comparing triptorelin to native GnRH found that triptorelin had 13 fold higher releasing activity for luteinizing hormone, and 21-fold higher releasing activity for follicle-stimulating hormone. Triptorelin is indicated for the palliative treatment of advanced prostate cancer.

Triptorelin is a synthetic decapeptide agonist analog of luteinizing hormone releasing hormone (LHRH). It works by decreasing the production of certain hormones, which reduces testosterone levels in the body. Animal studies comparing triptorelin to native GnRH found that triptorelin had 13 fold higher releasing activity for luteinizing hormone, and 21-fold higher releasing activity for follicle-stimulating hormone. Triptorelin is indicated for the palliative treatment of advanced prostate cancer.

Corticorelin ovine is an analogue of the naturally occurring human corticotropin-releasing hormone (hCRH) peptide. Corticorelin ovine is a potent stimulator of adrenocorticotropic hormone (ACTH) release from the anterior pituitary. ACTH stimulates cortisol production from the adrenal cortex. Corticorelin ovine was marketed under the brand name ACTHREL for use in differentiating pituitary and ectopic production of ACTH in patients with ACTH-dependent Cushing’s syndrome.

Teriparatide was manufactured under the brand name FORTEO. FORTEO contains recombinant human parathyroid hormone (1-34), [rhPTH(1-34)], which has an identical sequence to the 34 N-terminal amino acids (the biologically active region) of the 84-amino acid human parathyroid hormone, that regulates calcium and phosphate in the body. FORTEO is indicated for the treatment of postmenopausal women with severe osteoporosis who are at high risk of fracture or who have failed or are intolerant to previous osteoporosis therapy. In addition, Forteo is used for the treatment of osteoporosis associated with sustained systemic glucocorticoid therapy in men and women who are at increased risk for fracture. The biological actions of teriparatide is mediated through binding to specific high-affinity cell-surface receptors. Teriparatide is not expected to accumulate in bone or other tissues.

Glucagon is a polypeptide hormone identical to human glucagon that increases blood glucose and relaxes smooth muscle of the gastrointestinal tract. Glucagon is synthesized in a special non-pathogenic laboratory strain of Escherichia coli bacteria that has been genetically altered by the addition of the gene for glucagon. Glucagon generally elevates the concentration of glucose in the blood by promoting gluconeogenesis and glycogenolysis. Glucagon also decreases fatty acid synthesis in adipose tissue and the liver, as well as promoting lipolysis in these tissues, which causes them to release fatty acids into circulation where they can be catabolised to generate energy in tissues such as skeletal muscle when required. Glucose is stored in the liver in the form of the polysaccharide glycogen, which is a glucan (a polymer made up of glucose molecules). Liver cells (hepatocytes) have glucagon receptors. When glucagon binds to the glucagon receptors, the liver cells convert the glycogen into individual glucose molecules and release them into the bloodstream, in a process known as glycogenolysis. As these stores become depleted, glucagon then encourages the liver and kidney to synthesize additional glucose by gluconeogenesis. Glucagon turns off glycolysis in the liver, causing glycolytic intermediates to be shuttled to gluconeogenesis. Glucagon also regulates the rate of glucose production through lipolysis. Glucagon induces lipolysis in humans under conditions of insulin suppression (such as diabetes mellitus type 1). Glucagon increases blood glucose concentration and is used in the treatment of hypoglycemia. Glucagon administered through a parenteral route relaxes smooth muscle of the stomach, duodenum, small bowel, and colon. Glucagon is also indicated as a diagnostic aid in the radiologic examination of the stomach, duodenum, small bowel, and colon when diminished intestinal motility would be advantageous.

Anaritide (Auriculin-Registered Trademark) is a 25-amino-acid synthetic form of atrial natriuretic peptide. Scios Nova was developing anaritide acetate for use in the treatment, prevention and diagnosis of acute renal failure, heart failure and hypertension. Scios suspended development of AURICULIN® anaritide based upon the results of an interim analysis of data from a 250-patient Phase III study in oliguric acute renal failure. The study was suspended due to the low probability that a positive outcome could be obtained with respect to its primary clinical endpoint, dialysis-free survival.