title: 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.
authors.affiliation: Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan. yasuko@kais.kyoto-u.ac.jp
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Harada
authors.forename: Shigeo
authors.initials: S
authors.lastname: Harada
authors.forename: Izumi
authors.initials: I
authors.lastname: Kinoshita
authors.forename: Masaru
authors.initials: M
authors.lastname: Tanaka
authors.forename: Masatomo
authors.initials: M
authors.lastname: Tagawa
mesh_terms: D000818:Animals; D004064:Digestive System / Q000033:anatomy & histology / Q000254:growth & development; D006652:Histological Techniques; D007564:Japan; D009024:Morphogenesis; D010473:Perciformes / Q000254:growth & development*; D010902:Pituitary Gland / Q000033:anatomy & histology; D013961:Thyroid Gland / Q000033:anatomy & histology / Q000254:growth & development*; D013972:Thyrotropin
chemical_list: D013972:Thyrotropin