The role of thyroid hormones during the development of eye pigmentation in the Pacific bluefin tuna (Thunnus orientalis).
Thyroid hormones (THs) are essential for the embryonic and post-embryonic development of fish. We studied the role of THs during the early, post-embryonic, development of Pacific bluefin tuna. Embryos were treated with L-thyroxine (T(4)) or the anti-thyroid drug methimazole (MMI), and reared in microtitre plates for 3 days. Immersion in MMI, but not T(4), led to retardation of retinal pigment epithelium (RPE) pigmentation 3 days post-hatching (dph). Concurrent immersion in T(4) and MMI had no effect of RPE pigmentation. We also measured the expression of TRalphaA, TRalphaB, and TRbeta mRNA using real-time RT-PCR. Treatment with MMI significantly reduced TRbeta mRNA expression. Taken together these results suggest that the development of RPE pigmentation is mediated by TH, most likely via TRbeta.
Kawakami
Yutaka
Y
Department of Fisheries, Graduate School of Agriculture, Kinki University, Nara 631-8505, Japan. yutakakjp@yahoo.co.jp
Yokoi
Kenichi
K
Kumai
Hidemi
H
Ohta
Hiromi
H
D000818:Animals; D001947:Breeding; D005123:Eye / Q000187:drug effects* / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D008713:Methimazole / Q000494:pharmacology; D010857:Pigment Epithelium of Eye / Q000166:cytology / Q000187:drug effects; D010858:Pigmentation / Q000187:drug effects*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011988:Receptors, Thyroid Hormone / Q000235:genetics / Q000378:metabolism; D016019:Survival Analysis; D013974:Thyroxine / Q000494:pharmacology*; D014413:Tuna / Q000254:growth & development / Q000378:metabolism*
D012333:RNA, Messenger; D011988:Receptors, Thyroid Hormone; D008713:Methimazole; D013974:Thyroxine