Gonadorelin is a synthetic decapeptide prepared using solid phase peptide synthesis. GnRH is responsible for the release of follicle stimulating hormone and leutinizing hormone from the anterior pitutitary. In the pituitary GnRH stimulates synthesis and release of FSH and LH, a process that is controlled by the frequency and amplitude of GnRH pulses, as well as the feedback of androgens and estrogens. The pulsatility of GnRH secretion has been seen in all vertebrates, and it is necessary to ensure a correct reproductive function. Thus a single hormone, GnRH, controls a complex process of follicular growth, ovulation, and corpus luteum maintenance in the female, and spermatogenesis in the male. Its short half life requires infusion pumps for its clinical use. Gonadorelin is used for the treatment of amenorrhea, delayed puberty, and infertility the administration of gonadorelin is used to simulate the physiologic release of GnRH from the hypothalamus in treatment of delayed puberty, treatment of infertility caused by hypogonadotropic hypogonadism, and induction of ovulation in those women with hypothalamic amenorrhea. This results in increased levels of pituitary gonadotropins LH and FSH, which subsequently stimulate the gonads to produce reproductive steroids.

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.