title: Inhibiting roles of melanin-concentrating hormone for skin pigment dispersion in barfin flounder, Verasper moseri.
abstract: Barfin flounders change their surface color pattern to match their background. We have reported evidence of the association between hormones and body color changes in this fish. First, bolus intraperitoneal injection with melanin-concentrating hormone (MCH) immediately turned the skin color pale, while injection with melanocyte-stimulating hormone (MSH) did not change the skin color. Second, gene expression levels of MCH change in response to background color, while those of MSH do not. We also reported the expression of an MCH receptor gene (Mch-r2) in the skin of this fish. In this study, we aimed to further evaluate the roles of MCH in skin color change. First, long-term adaptation of adult barfin flounder to black or white background colors induced significantly different pigment migration patterns in both melanophores and xanthophores (P<0.05). However, continuous intraperitoneal injection with MCH did not influence chromatophore proliferation. Then, using in vitro experiments, we found that MCH aggregates both melanophores and xanthophores, and inhibits the pigment-dispersing activity of MSH in a similar manner. Finally, we identified transcripts of Mch-r2 in cells isolated from both melanophores and xanthophores. Taken together, the evidence suggests that MCH aggregates pigments via MCH-R2 in concert with the nervous system by overcoming the melanin-dispersing activities of MSH in barfin flounder.
authors.affiliation: School of Marine Biosciences, Kitasato University, Ofunato, Iwate 022-0101, Japan. mizusawa@kitasato-u.ac.jp
authors.forename: Kanta
authors.initials: K
authors.lastname: Mizusawa
authors.forename: Yuki
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Sunuma
authors.forename: Takashi
authors.initials: T
authors.lastname: Asahida
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Saito
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Takahashi
mesh_terms: D000818:Animals; D005432:Flounder; D007028:Hypothalamic Hormones / Q000494:pharmacology*; D008543:Melanins / Q000494:pharmacology*; D009074:Melanocyte-Stimulating Hormones; D008547:Melanophores / Q000378:metabolism; D010907:Pituitary Hormones / Q000494:pharmacology*; D011979:Receptors, Pituitary Hormone / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012867:Skin / Q000378:metabolism; D012880:Skin Pigmentation / Q000187:drug effects*
chemical_list: D007028:Hypothalamic Hormones; D008543:Melanins; D010907:Pituitary Hormones; D011979:Receptors, Pituitary Hormone; C092274:melanin-concentrating hormone receptor; C019463:melanin-concentrating hormone; D009074:Melanocyte-Stimulating Hormones