Thyroid Gland Development in a Neotenic Goby (Ice Goby, Leucopsarion petersii) and a Common Goby (Ukigori, Gymnogobius urotaenia) during Early Life Stages

Abstract In order to study the characteristics of neoteny in teleosts, development of the thyroid system and digestive tract of a neotenic goby (ice goby, Leucopsarion petersii) and a non-neotenic goby (ukigori, Gymnogobius urotaenia) were compared. In juvenile ukigori, the intestine was found to be convoluted once in the antero-midpart, and gastric glands were present. In the ice goby, the alimentary canal was straight, and no gastric gland was observed even in adult, suggesting that the ice goby retains larval features, not only in appearance but also in internal organs. A marked difference was also found in the thyroid system. In ukigori, activity of the thyroid gland and thyroid stimulating hormone (TSH) cells increased between flexion and postflexion larval phases. However, in the ice goby, thyroid glands remained inactive, and no TSH cells were observed. A delayed development of the thyroid system was suggested as a major factor contributing to neoteny in the ice goby.

[1]  T. Hirano,et al.  Changes in whole body concentrations of thyroid hormones and cortisol in metamorphosing conger eel , 1991, Journal of Comparative Physiology B.

[2]  S. Miwa,et al.  Histological changes in the pituitary-thyroid axis during spontaneous and artificially-induced metamorphosis of larvae of the flounder Paralichthys olivaceus , 1987, Cell and Tissue Research.

[3]  T. Kaneko,et al.  Response of a Neotenic Goby, Ice Goby (Leucopsarion petersii), to Thyroid Hormone and Thiourea Treatments , 2003, Zoological science.

[4]  K. Yamauchi,et al.  Developmental changes in pituitary-thyroid axis, and formation of gonads in leptocephali and glass eels of Anguilla spp. , 2000 .

[5]  P. Rosenkilde,et al.  What mechanisms control neoteny and regulate induced metamorphosis in urodeles? , 1996, The International journal of developmental biology.

[6]  A. Youngson,et al.  Thyroid hormone levels in Atlantic salmon (Salmo salar) during the return migration from the ocean to spawn , 1993 .

[7]  H. M. Dye,et al.  Changes in plasma thyroid hormone levels in pink salmon, Oncorhynchus gorbuscha, during their spawning migration in the Fraser River (Canada) , 1989 .

[8]  J. Youson.  2 First Metamorphosis , 1988 .

[9]  A. W. Kendall.  Early life stages of fishes and their characters , 1984 .

[10]  Yoshirou Yamamoto,et al.  Development of the Pituitary and Thyroid Gland in the Medaka, Oryzias latipes , 1980 .

[11]  Y. Dotsu.  On eggs, larvae and juveniles of Gobioid fishes , 1979 .

[12]  R. Donabedian.  Comparative Vertebrate Endocrinology , 1977, The Yale Journal of Biology and Medicine.

[13]  Masaru Tanaka.  Studies on the Structure and Function of the Digestive System in Teleost Larvae III.Development of the Digestive System during Postlarval Stage , 1971 .

[14]  Y. Honma,et al.  Histological changes in the organs and tissues of the gobiid fishes throughout the life-span-2 The hypophyseal target organs of the ice-goby, Leucopsarion petersii Hilgendorf , 1970 .