mel·a·no·cyte-stim·u·lat·ing hormone 
(mĕlə-nō-sīt′stĭm′yə-lā′tĭng, mə-lănə-)
(mĕlə-nō-sīt′stĭm′yə-lā′tĭng, mə-lănə-)n. Abbr. MSH
A hormone secreted by the pituitary gland that regulates skin color in humans and other vertebrates by stimulating melanin synthesis in melanocytes and melanin granule dispersal in melanophores. Also called intermedin.