Melanin-concentrating hormone is not involved in luminescence emission in the velvet belly lanternshark, Etmopterus spinax

Luminous deep-sea etmopterid sharks use hormonal control to regulate bioluminescence. Melatonin and prolactin trigger light emission and, conversely, α-melanocyte stimulating hormone actively reduces ongoing luminescence. Interestingly, these hormones are also known as regulators of skin pigment motion in teleost fish and epipelagic elasmobranchs. On the other hand, the melanin-concentrating hormone (MCH) is another regulator of the skin pigment...