Early morphological background adaptation in the medaka Oryzias latipes depends on growth hormone receptor type 1.

DELGADIN, T.H.; CASTAÑEDA CORTÉS, D.C.; SACKS, C.; BRECCIA, A.; FERNANDINO, J.I.; VISSIO, P

Congreso; X Latin American Society for Developmental Biology Meeting; 2019

Latin American Society for Developmental Biology

Morphological background adaptation is both an endocrine and a nervous response to the surrounding environment that many fishes are able to display owing to changes in the amount and shape of specialized cells called chromatophores located in the skin. However, it is not known if such a process takes place at early developmental stages. Somatolactin (SL) is a pituitary hormone present in fish that has been related to skin pigmentation. Although growth hormone receptor type 1 (GHR1) has been suggested to be the SL receptor in some fish species and it has been demonstrated an association between SL and GHR1 with adaptation to dark backgrounds, there is evidence against to GHR1 as SL receptor. The aim of this work was to evaluate at what moment on ontogeny morphological adaptation to background first occur and if it depends upon GHR1, the putative SLR. We analyzed the amount of chromatophores in medakas reared from egg fertilization to white or black backgrounds at 9, 21, 16, 21 and 25 days post hatching (dph). We repeated this protocol at 16 and 21 dph for CRIPSR/Cas9 GHR1 mutant medaka and Cas9 controls. By 16 dph, black adapted medaka presented more melanophores than white adapted ones (p=0.0001). This adaptation was severely reduced in GHR1 deficient medaka (p