Adrenocorticotropic Hormone and Cyclic Adenosine Monophosphate are Involved in the Control of Shark Bioluminescence
Laurent Duchateleta✉, Jérôme Delroisseb c, Nicolas Pintea, Keiichi Satod e, Hsuan-Ching Hans Hof g, Jérôme Mallefeta
- aMarine Biology Laboratory Earth and Life Institute Université Catholique de Louvain Louvain‐La‐Neuve Belgium
- bResearch Institute for Biosciences, Biology of Marine Organisms and Biomimetics University of Mons Mons Belgium
- cResearch Institute for Biosciences, Biology of Marine Organisms and Biomimetics, University of Mons, Mons, Belgium
- dOkinawa Churaumi Aquarium Motobu‐cho Okinawa Prefecture Japan
- eOkinawa Churaumi Aquarium, Motobu-cho, Okinawa Prefecture, Japan
- fNational Museum of Marine Biology and Aquarium Checheng Pingtung Taiwan
- gNational Museum of Marine Biology and Aquarium, Checheng, Pingtung, Taiwan
- ✉Corresponding author
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Abstract
Among Etmopteridae and Dalatiidae, luminous species use hormonal control to regulate bioluminescence. Melatonin (MT) triggers light emission and, conversely, alpha melanocyte-stimulating hormone (α-MSH) actively reduces ongoing luminescence. Prolactin (PRL) acts differentially, triggering light emission in Etmopteridae and inhibiting it in Dalatiidae. Interestingly, these hormones are also known as regulators of skin pigment movements in vertebrates. One other hormone, the adrenocorticotropic hormone (ACTH), also members of the skin pigmentation regulators, is here pharmacologically tested on the light emission. Results show that ACTH inhibits luminescence in both families. Moreover, as MT and α-MSH/ACTH receptors are members of the G-protein coupled receptor (GPCR) family, we investigated the effect of hormonal treatments on the cAMP level of photophores through specific cAMP assays. Our results highlight the involvement of ACTH and cAMP in the control of light emission in sharks and suggest a functional similarity between skin pigment migration and luminescence control, this latter being mediated by pigment movements in the light organ-associated iris-like structure cells.