Alpha-melanocyte stimulating hormone (α-MSH) and melanin-concentrating hormone (MCH) stimulate phagocytosis by head kidney leucocytes of rainbow trout (Oncorhynchus mykiss) in vitro

• Published in: Fish & shellfish immunology Vol. 8; no. 8; pp. 631 - 638
• Main Authors: Harris, James, Bird, David J.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.1998
• Subjects: alpha-melanocyte stimulating hormone; immuno-endocrinology; melanin-concentrating hormone; Oncorhynchus mykiss; phagocytosis; rainbow trout; immuno-endocrinology; phagocytosis; melanin-concentrating hormone; rainbow trout; alpha-melanocyte stimulating hormone
• ISSN: 1050-4648; 1095-9947
• DOI: 10.1006/fsim.1998.0172

Alpha-melanocyte stimulating hormone (α-MSH) and melanin-concentrating hormone (MCH) are two peptides with antagonistic roles in the regulation of skin pigmentation in teleost fish. Both have also been implicated in the modulation of the stress response via the hypothalamo-pituitary-adrenal (HPA) axis in fish and other vertebrates. Alpha-MSH is also known to be a potent immunomodulatory peptide in mammals, while both hormones have been shown to influence the immune responses of troutin vitro. Head kidney phagocytes (macrophages and neutrophils) were exposed to α-MSH at concentrations of 0·05 to 10nMin vitro for 60min and the phagocytic activity of glass-adherent cells was assessed microscopically. At 1, 5 and 10nMα-MSH significantly increased the percentage of phagocytes that ingested heat-killed yeast cells. Percentage phagocytosis was also significantly increased when cells were exposed to 0·1, 1 and 10nM des-acetyl-α-MSH. Whenα-MSH and MCH were added to cells together, at concentrations of 1nM and 50nM respectively, the stimulatory effects of both hormones were diminished. The results suggest that these peptides may play an immunomodulatory role in the fish immune system.