Urocortin is a peptide composed of 40 amino acids. Urocortin is composed of a single alpha helix structure. The human UCN gene contains two exons, and the entirety of the coding region is contained within the second exon.[4] Urocortin is expressed widely in the central and peripheral nervous systems, with a pattern similar to that of CRF.[5] Areas of similarity between urocortin and CRF expression include the supraoptic nucleus and the hippocampus.[6][7] Urocortin is also expressed in areas distinct from CRF expression; these areas notably include the median eminence, the Edinger-Westphal nucleus, and the sphenoid nucleus.[7] Additionally, Urocortin is expressed in peripheral tissues such as the heart.[8]
Urocortin is known to interact both with the CRF type 1 and CRF type 2 receptors.[9][10][11] Furthermore, Urocortin is thought to be the primary ligand for the CRF type 2 receptor, as it has higher binding affinity for the CRF type 2 receptor than CRF.[9] Additionally, urocortin interacts with CRF Binding Protein in the mammalian brain.[12]
Stress response and social behavior
Urocortin is closely related to CRF, which mediates the mammalian stress response. Urocortin is consequently implicated in a number of stress responses, primarily relating to appetite and food intake. Administration of urocortin to the central nervous system of mice and rats has been shown to decrease appetite.[13] Additionally, central urocortin treatment increases anxiety-linked behaviors and increases motor activity in mice and rats.[13] These general anxiety-linked behaviors are likely induced through the CRF type 1 receptor, and the appetite behaviors are likely induced through the CRF type 2 receptor. The reduction in appetite from urocortin treatment could be a result of suppression of gastric emptying and/or hypoglycemia, which have been shown to result from urocortin treatment.[14] Urocortin expression is stimulated in response to osmotic stress; water deprivation in rats has been shown to induce urocortin expression in the supraoptic nucleus.[15]
Montane Voles and Meadow Voles are closely related species of voles which are regularly studied as a model for social and mating behavior. The distribution of urocortin-expressing neurons differs in meadow voles compared to montane voles, suggesting urocortin may also play a role in modulating social behavior in some species.[16]
Cardiovascular effects
Urocortin has been shown to induce increases in heart rate and coronary blood flow when applied peripherally.[8] These effects are likely mediated through the CRF type 2 receptor, as this receptor is found in the cardiac atria and ventricles.[17] Urocortin also functions to protect cardiovascular tissue from ischemic injury.[18] Urocortin's cardiovascular effects separate it from other members of the CRF family, and likely represent its primary biological function.
In non-mammals
Urocortin is not present in all non-mammals; the closet analogue in teleost fish is urotensin I.[19] However, in amphibian species such as Xenopus laevis, urocortin is expressed in tissues such as brain, pituitary, kidney, heart, and skin. Urocortin in Xenopus has been shown to increase cAMP accumulation and inhibit appetite[19]
References
↑Zhao L, Donaldson CJ, Smith GW, Vale WW (May 1998). "The structures of the mouse and human urocortin genes (Ucn and UCN)". Genomics. 50 (1): 23–33. doi:10.1006/geno.1998.5292. PMID9628819.
↑Tsarev OB (July 1977). "[Dynamics of matrix synthesis in molecular biophysics. II. Principle of insertability and the single-valued solution of feedback tasks]". Biofizika. 22 (2): 197–200. PMID861256.
↑Zhao L, Donaldson CJ, Smith GW, Vale WW (May 1998). "The structures of the mouse and human urocortin genes (Ucn and UCN)". Genomics. 50 (1): 23–33. doi:10.1006/geno.1998.5292. PMID9628819.
↑ 7.07.1Morin SM, Ling N, Liu XJ, Kahl SD, Gehlert DR (1999). "Differential distribution of urocortin- and corticotropin-releasing factor-like immunoreactivities in the rat brain". Neuroscience. 92 (1): 281–91. doi:10.1016/S0306-4522(98)00732-5. PMID10392850.
↑ 9.09.1Vaughan J, Donaldson C, Bittencourt J, Perrin MH, Lewis K, Sutton S, Chan R, Turnbull AV, Lovejoy D, Rivier C (November 1995). "Urocortin, a mammalian neuropeptide related to fish urotensin I and to corticotropin-releasing factor". Nature. 378 (6554): 287–92. doi:10.1038/378287a0. PMID7477349.
↑Gottowik J, Goetschy V, Henriot S, Kitas E, Fluhman B, Clerc RG, Moreau JL, Monsma FJ, Kilpatrick GJ (October 1997). "Labelling of CRF1 and CRF2 receptors using the novel radioligand, [3H]-urocortin". Neuropharmacology. 36 (10): 1439–46. doi:10.1016/S0028-3908(97)00098-1. PMID9423932.
↑Donaldson CJ, Sutton SW, Perrin MH, Corrigan AZ, Lewis KA, Rivier JE, Vaughan JM, Vale WW (May 1996). "Cloning and characterization of human urocortin". Endocrinology. 137 (5): 2167–70. doi:10.1210/en.137.5.2167. PMID8612563.
↑Baigent SM, Lowry PJ (2000). "Urocortin is the principal ligand for the corticotrophin-releasing factor binding protein in the ovine brain with no evidence for a sauvagine-like peptide". Journal of Molecular Endocrinology. 24 (1): 53–63. doi:10.1677/jme.0.0240053. PMID10656997.
↑Hara Y, Ueta Y, Isse T, Kabashima N, Shibuya I, Hattori Y, Yamashita H (1997). "Increase of urocortin-like immunoreactivity in the rat supraoptic nucleus after dehydration but not food deprivation". Neuroscience Letters. 229 (1): 65–8. doi:10.1016/S0304-3940(97)00419-9. PMID9224803.
↑Brar BK, Jonassen AK, Stephanou A, Santilli G, Railson J, Knight RA, Yellon DM, Latchman DS (March 2000). "Urocortin protects against ischemic and reperfusion injury via a MAPK-dependent pathway". The Journal of Biological Chemistry. 275 (12): 8508–14. doi:10.1074/jbc.275.12.8508. PMID10722688.
↑ 19.019.1Boorse GC, Crespi EJ, Dautzenberg FM, Denver RJ (November 2005). "Urocortins of the South African clawed frog, Xenopus laevis: conservation of structure and function in tetrapod evolution". Endocrinology. 146 (11): 4851–60. doi:10.1210/en.2005-0497. PMID16037378.
Further reading
Inui A, Asakawa A, Bowers CY, Mantovani G, Laviano A, Meguid MM, Fujimiya M (March 2004). "Ghrelin, appetite, and gastric motility: the emerging role of the stomach as an endocrine organ". FASEB Journal. 18 (3): 439–56. doi:10.1096/fj.03-0641rev. PMID15003990.
Huang Y, Yao XQ, Lau CW, Chan YC, Tsang SY, Chan FL (Mar 2004). "Urocortin and cardiovascular protection". Acta Pharmacol Sin. 25 (3): 257–65.
Takahashi, Kazuhiro (2004). "Translational medicine in fish-derived peptides: From fish endocrinology to human physiology and diseases". Endocrine Journal (Kyoto, Japan). 51 (1): 1–17. doi:10.1507/endocrj.51.1.
Iino K, Sasano H, Oki Y, Andoh N, Shin RW, Kitamoto T, Totsune K, Takahashi K, Suzuki H, Nagura H, Yoshimi T (November 1997). "Urocortin expression in human pituitary gland and pituitary adenoma". The Journal of Clinical Endocrinology and Metabolism. 82 (11): 3842–50. doi:10.1210/jc.82.11.3842. PMID9360550.
Gottowik J, Goetschy V, Henriot S, Kitas E, Fluhman B, Clerc RG, Moreau JL, Monsma FJ, Kilpatrick GJ (October 1997). "Labelling of CRF1 and CRF2 receptors using the novel radioligand, [3H]-urocortin". Neuropharmacology. 36 (10): 1439–46. doi:10.1016/S0028-3908(97)00098-1. PMID9423932.
Bamberger CM, Wald M, Bamberger AM, Ergün S, Beil FU, Schulte HM (February 1998). "Human lymphocytes produce urocortin, but not corticotropin-releasing hormone". The Journal of Clinical Endocrinology and Metabolism. 83 (2): 708–11. doi:10.1210/jc.83.2.708. PMID9467598.
Takahashi K, Totsune K, Sone M, Murakami O, Satoh F, Arihara Z, Sasano H, Iino K, Mouri T (1998). "Regional distribution of urocortin-like immunoreactivity and expression of urocortin mRNA in the human brain". Peptides. 19 (4): 643–7. doi:10.1016/S0196-9781(98)00012-6. PMID9622018.
Iino K, Sasano H, Oki Y, Andoh N, Shin RW, Kitamoto T, Takahashi K, Suzuki H, Tezuka F, Yoshimi T, Nagura H (January 1999). "Urocortin expression in the human central nervous system". Clinical Endocrinology. 50 (1): 107–14. doi:10.1046/j.1365-2265.1999.00624.x. PMID10341863.
Watanabe F, Oki Y, Ozawa M, Masuzawa M, Iwabuchi M, Yoshimi T, Nishiguchi T, Iino K, Sasano H (1999). "Urocortin in human placenta and maternal plasma". Peptides. 20 (2): 205–9. doi:10.1016/S0196-9781(98)00175-2. PMID10422876.
Slominski A, Roloff B, Curry J, Dahiya M, Szczesniewski A, Wortsman J (February 2000). "The skin produces urocortin". The Journal of Clinical Endocrinology and Metabolism. 85 (2): 815–23. doi:10.1210/jc.85.2.815. PMID10690896.
Muramatsu Y, Fukushima K, Iino K, Totsune K, Takahashi K, Suzuki T, Hirasawa G, Takeyama J, Ito M, Nose M, Tashiro A, Hongo M, Oki Y, Nagura H, Sasano H (December 2000). "Urocortin and corticotropin-releasing factor receptor expression in the human colonic mucosa". Peptides. 21 (12): 1799–809. doi:10.1016/S0196-9781(00)00335-1. PMID11150640.
Muramatsu Y, Sugino N, Suzuki T, Totsune K, Takahashi K, Tashiro A, Hongo M, Oki Y, Sasano H (March 2001). "Urocortin and corticotropin-releasing factor receptor expression in normal cycling human ovaries". The Journal of Clinical Endocrinology and Metabolism. 86 (3): 1362–9. doi:10.1210/jc.86.3.1362. PMID11238533.
Hsu SY, Hsueh AJ (May 2001). "Human stresscopin and stresscopin-related peptide are selective ligands for the type 2 corticotropin-releasing hormone receptor". Nature Medicine. 7 (5): 605–11. doi:10.1038/87936. PMID11329063.
Kimura Y, Takahashi K, Totsune K, Muramatsu Y, Kaneko C, Darnel AD, Suzuki T, Ebina M, Nukiwa T, Sasano H (January 2002). "Expression of urocortin and corticotropin-releasing factor receptor subtypes in the human heart". The Journal of Clinical Endocrinology and Metabolism. 87 (1): 340–6. doi:10.1210/jc.87.1.340. PMID11788672.
Florio P, Arcuri F, Ciarmela P, Runci Y, Romagnoli R, Cintorino M, Di Blasio AM, Petraglia F (May 2002). "Identification of urocortin mRNA and peptide in the human endometrium". The Journal of Endocrinology. 173 (2): R9–14. doi:10.1677/joe.0.173R009. PMID12010647.
Arcuri F, Cintorino M, Florio P, Floccari F, Pergola L, Romagnoli R, Petraglia F, Tosi P, Teresa Del Vecchio M (August 2002). "Expression of urocortin mRNA and peptide in the human prostate and in prostatic adenocarcinoma". The Prostate. 52 (3): 167–72. doi:10.1002/pros.10094. PMID12111693.
Ikeda K, Tojo K, Oki Y, Nakao K (September 2002). "Urocortin has cell-proliferative effects on cardiac non-myocytes". Life Sciences. 71 (16): 1929–38. doi:10.1016/S0024-3205(02)01945-8. PMID12175707.