Effect of Exogenous Thyroxine on Mophology and Development of Thyroid Gland in Marble Goby Oxyeleotris marmoratus Bleeker Larvae

摘要

This study was conducted to examine effect of the exogenous thyroxine (T ) on ontogeny of thyroid 4 gland in marble goby larvae and to found out whether the exogenous T can alter the follicle structure and the 4 level of T in marble goby. The larvae were exposed for 1 h in T solution at 0.1 ppm. Untreated larvae (control) 4 4 were not immersed in T hormone. It was found that T levels in treated larvae were higher than control, but the 44 development patterns in both treated larvae and control were similar in which occurred a decreasing of T levels 4 from 3-7 days after hatching (dAH), and then increased again from 10 dAH onwards. The histological evidences that the follicles structure in treated larvae were difference than control, in which suggested abundance of thyroid hormone. These findings suggested that thyroid hormones (THs) may play an important role during early larval’s life and metamorphosis period. High total T levels in the treated larvae suggested that exogenous 4T has a predictable role to increase T level, especially in early larval stage of marble goby.