Sermorelin, a 29 amino acid analog of human growth hormone-releasing hormone (GHRH), is the shortest synthetic peptide with a full biological activity of GHRH which is used as a diagnostic agent to assess growth hormone (GH) secretion for the purpose of diagnosing growth hormone deficiency. Intravenous and subcutaneous sermorelin specifically stimulate growth hormone secretion from the anterior pituitary. Sermorelin binds to the growth hormone releasing hormone receptor and mimics native GRF in its ability to stimulate growth hormone secretion. Hormone responses to intravenous sermorelin appear to be a rapid and relatively specific test for the diagnosis of growth hormone deficiency.

Saralasin is an angiotensin II analogue which was developed for the treatment of hypertension in 1970s. For many years saralasin was supposed to be angiotensin receptors blocker, but recent studies have revealed that its pharmacological action can be explained by agonistic behavior toward angiotensin II receptor. The drug was approved by FDA under the name Sarenin, however, it is no longer available on the market.

Seractide is a polypeptide hormone corresponding to thirty-nine amino acids of human corticotropin that differs from full-length human corticotropin at four positions. Seractide is potent endogenous melanocortin receptor 2 (MC ) agonist. Seractide stimulates the cortex of the adrenal gland and boosts the synthesis of corticosteroids, mainly glucocorticoids but also sex steroids (androgens). Seractide, was approved by FDA in 1978, but was never marketed. The Seractide, that was ultimately withdrawn by FDA in 2014 for safety reasons.

Somatorelin is 29 amino acid analogue of human growth hormone-releasing hormone used as a diagnostic agent for determining growth hormone deficiency. Growth-hormone-releasing hormone (GHRH, somatoliberin) is the hypothalamic peptide hormone that specifically stimulates synthesis and release of growth hormone (GH, somatotropin) by somatotrope cells of the anterior pituitary gland. The hypothalamic hormone growth hormone (GH)-releasing hormone (GHRH) acts on specific GHRH receptors (GHRH-R) in the anterior pituitary gland to stimulate the synthesis and secretion of GH and to promote somatotrope expansion. Somatorelin is applied to determine the somatotropic function of the anterior pituitary gland in cases of suspected growth hormone deficiency. The test distinguishes between pituitary and hypothalamic disorders but is not suitable as a screening test for growth hormone deficiencies. Somatorelin has been used in trials studying the treatment of Aging, Elderly, Sleep Disorders, Hormone Deficiency, and Mild Cognitive Impairment.

Corticorelin (Xerecept) is a synthetic analog of the naturally occurring human peptide corticotropin-releasing factor (CRF). Corticotropin-releasing factor is the predominant regulator of adrenocorticotropic-hormone (ACTH) formation and release by the pituitary. In addition to its primary location in the hypothalamic paraventricular nucleus, endogenous CRF has also been identified in cerebral cortical interneurons, the limbic system, brain stem and spinal cord. Several studies have indicated the ability of CRF to reduce the brain edema caused by brain tumors. Clinical trials with the Corticorelin (Xerecept) have indicated that this drug has a distinct advantage over classical corticosteroids in the treatment of brain edema. Fewer and/or milder side effects have been reported for corticorelin compared with dexamethasone, although at higher doses of corticorelin several side effects, including hypotension and transient flushing, have been reported.