Involvement of somatolactin in background adaptation of the cichlid fish Cichlasoma dimerus.
Somatolactin (SL) is a pituitary hormone present exclusively in fish that is involved in different physiological processes. The role of SL was evaluated in Cichlasoma dimerus (Teleostei, Perciformes) exposed for 10 days to a black and white background (BB and WB). Changes in alpha-melanophore stimulating hormone (alphaMSH) and melanin concentrating hormone (MCH) cells were also analyzed for comparison with SL. A melanin dispersing effect was observed in fish exposed to a BB, while a concentrating one was observed in those exposed to a WB. By Western blot, three SL-immunoreactive (ir) bands (32, 28 and 23.5 kD) were evidenced. Pituitary SL-ir levels were 2.66- and 2.67-fold greater in the 32 Kd and 28 kD bands, respectively, in BB fish compared with those of WB fish. The SL-ir 23.5 Kd band was not included in the analysis because of its unknown identity. In addition, SL-ir cell number and area were significantly higher in the BB condition (BB 22.73+/-1.46, WB 7.37+/-0.54 and BB 27.39+/-1.00 microm2; WB: 16.61+/-0.65 microm2). No significant differences were observed in the number of the hypothalamic MCH-ir neurons. However, a significant difference was observed in their nuclear area (BB 11.61+/-0.42 microm2, WB 17.80+/-0.84 microm2). alphaMSH-ir cells showed a marked increased in number (BB 35.96+/-1.22, WB 24.36+/-1.04), but no significant differences were observed in the cell area. In conclusion, this study presented clear evidence towards a possible involvement of SL in the adaptation to background colors in teleost together with alphaMSH and MCH.
Laboratorio de Embriología Animal, Dpto. de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina. mcanepa@bg.fcen.uba.ar
Maximiliano Martín
MM
Cánepa
Matías
M
Pandolfi
María Cristina
MC
Maggese
Paula Gabriela
PG
Vissio
D000222:Adaptation, Physiological; D000818:Animals; D002452:Cell Count; D002467:Cell Nucleus; D023681:Cichlids / Q000502:physiology*; D004777:Environment; D029941:Fish Proteins / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism*; D007028:Hypothalamic Hormones / Q000378:metabolism; D007031:Hypothalamus / Q000166:cytology / Q000378:metabolism; D008543:Melanins / Q000378:metabolism; D009074:Melanocyte-Stimulating Hormones / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D010902:Pituitary Gland / Q000737:chemistry / Q000378:metabolism; D010907:Pituitary Hormones / Q000378:metabolism*; D012867:Skin / Q000378:metabolism*; D012880:Skin Pigmentation / Q000502:physiology*
D029941:Fish Proteins; D006023:Glycoproteins; D007028:Hypothalamic Hormones; D008543:Melanins; D010907:Pituitary Hormones; C064448:somatolactin protein, fish; C019463:melanin-concentrating hormone; D009074:Melanocyte-Stimulating Hormones