What is Gonadorelin?
Gonadorelin is a synthetic oligopeptide that can mimic the effects of gonadotropin-releasing hormone agonists. The gonadotropin-releasing hormone (GnRH) is a decapeptide secreted by the hypothalamus that controls the release of LH and FSH from the anterior pituitary. GnRH agonists have been used for a long time to inhibit the secretion of LH and FSH for different purposes. That is why scientists assume that Gonadorelin could also be responsible for the secretion of the previously mentioned gonadotropins.
According to different studies, Gonadorelin also showed effects on the menstrual cycle and has been studied in breast and prostate cancer and dementia cases, where it showed great effects.
Gonadorelin Research Benefits
Effects of Gonadorelin on the Menstrual Cycle
The menstrual cycle is the result of the hypothalamus, pituitary, ovary, and endometrium actions. The hypothalamus places the beat for the menstrual cycle by setting the pulses of GnRH. Pulses appear every 1-1.5 h in the follicular phase and every 2-4 h in the luteal phase of the cycle. According to the “Gonadotropin-releasing hormone agonist treatment in postmenopausal women with hyperandrogenism of ovarian origin” study, GnRH secretion stimulates the pituitary gland to secrete luteinizing hormone (LH) and follicle-stimulating hormone (FSH). The pituitary gland turns the rhythm set by the hypothalamus into a signal, LH, and FSH secretion, that can be seen by the ovarian follicle.
GnRH Potentially Rescues Cognition in Dementia
Many problems can be related to the neuroendocrine area. That includes Alzheimer's disease, dementia, cognitive dysfunction, and Parkinson's disease. Throughout brain development, the amount of myelin increases in the cortical grey matter, together with better cognition.
MiR-200 in the POA are the compounds that normalize the expression of myelination-related genes in the hippocampus of the mice. Scientists assume that pulsatile GnRH secretion at the time of puberty could be a signal for supreme brain ripening.
Animal cases of dementia, including AD type, show an upregulation of myelination genes that are the same as those found in mice. Blood concentrations of LH and FSH increase with age. A rise in FSH is followed by a fall in inhibin levels with the aging process. With this knowledge, scientists assume that the application of GnRH could potentially lead to higher levels of FSH and LH, and that way, this hormonal therapy could be effective in the fields of dementia, Alzheimer's disease, and other memory problems.
Effect of Gonadorelin on Fertility and Reproductive Health
As previously mentioned, gametes' development is controlled by the two gonadotropins, follicle-stimulating hormone (FSH) and luteinizing hormone (LH), which come from the pituitary. FSH and LH are under the control of gonadotropin-releasing hormone (GnRH). This peptide is the same structure molecule in males and females, and because of that, inactivation of the GnRH affects fertility in males and females at the same level.
The lower amount of GnRH results in the interruption of regular menstrual cycles, gonadal atrophy, and blockade of the gestation process in different species of mammals. Levels of GnRH, but also Gonadorelin, which, according to the knowledge acquired so far, has a role in imitating gonadotropin-releasing hormone agonists, have to be stable; otherwise, disarranged levels of LH and FSH could further disrupt the menstrual cycle.
Doses of GnRH initiate the process of testosterone production and spermatogenesis in mammalian males. The inclusion of GnRH in animal subjects has been shown to raise testosterone capacity more than natural levels, which has demonstrated the effects of GnRH.
Gonadorelin and the Prostate and Breast Cancer Therapy
Prostate and breast cancer are forms of malignancy which show a high mortality percentage. The “Hormonal therapy of prostate cancer” by F. Labrie describes how, after identifying gonadotropin-releasing hormone (GnRH), analogs that lower LH production and androgen secretion were synthesized.
Some studies have shown an improvement in progression-free survival and overall survival when leuprolide (GnRH agonist) is used. This survival level increase was most specific for those patients with minimal disease stages. GnRH agonists as a base of therapy for breast cancer showed no change in follicular count or ovarian size. Inhibition of the pituitary-gonadal axis is the main ground for oncological applications of luteinizing hormone-releasing hormone (LH-RH).
New therapies are being developed based on GnRH, restricting growth factors or their receptors. Other approaches consider cytotoxic analogs of GnRH, which can be specifically targeted to the receptors of these peptides in primary cancers and their metastases.
Summary
Gonadorelin can be considered as a synthetic version of the gonadotropin-releasing hormone. This peptide is a major regulator in the secretion of gonadotropins (LH and FSH). Due to its bioactivity, scientists assume that this peptide shows potential effects on fertility and reproductive health, as well as on the menstrual cycle and cancer and dementia therapy. Further research should show even better results in previously mentioned arias.
Please note that Gonadorelin is not approved for human use and is currently available only for research purposes.
References:
Gillies PS, Faulds D, Balfour JA, Perry CM. Ganirelix. Drugs. 2000 Jan;59(1):107-11; discussion 112-3.
Talwar GP, Raghupathy R. Anti-fertility vaccines. Vaccine. 1989 Apr;7(2):97-101.
Moon, T. D. (1992). Prostate Cancer. Journal of the American Geriatrics Society, 40(6), 622–627.
Ruddy, K. J., & Partridge, A. H. (2009). Fertility. Cancer Treatment and Research, 367–385.
Schally AV, Comaru-Schally AM, Nagy A, Kovacs M, Szepeshazi K, Plonowski A, Varga JL, Halmos G. Hypothalamic hormones and cancer. Front Neuroendocrinol. 2001 Oct;22(4):248-Barbieri RL. The endocrinology of the menstrual cycle. Methods Mol Biol. 2014;1154:145-69.
Manfredi-Lozano M, Leysen V, Adamo M, Paiva I, Rovera R, Pignat JM, Timzoura FE, Candlish M, Eddarkaoui S, Malone SA, Silva MSB, Trova S, Imbernon M, Decoster L, Cotellessa L, Tena-Sempere M, Claret M, Paoloni-8.Giacobino A, Plassard D, Paccou E, Vionnet N, Acierno J, Maceski AM, Lutti A, Pfrieger F, Rasika S, Santoni F, Boehm U, Ciofi P, Buée L, Haddjeri N, Boutillier AL, Kuhle J, Messina A, Draganski B, Giacobini P, Pitteloud N, Prevot V. GnRH replacement rescues cognition in Down syndrome. Science. 2022 Sep 2;377(6610):eabq4515.
Rehman HU, Masson EA. Neuroendocrinology of aging. Age Ageing. 2001 Jul;30(4):279-87.