info:eu-repo/semantics/article
Pituitary–thyroid axis development during the larval–juvenile transition in the pejerrey Odontesthes bonariensis
Fecha
2017-09Registro en:
Chalde, Tomás; Miranda, Leandro Andres; Pituitary–thyroid axis development during the larval–juvenile transition in the pejerrey Odontesthes bonariensis; Wiley Blackwell Publishing, Inc; Journal of Fish Biology; 91; 3; 9-2017; 818-834
0022-1112
CONICET Digital
CONICET
Autor
Chalde, Tomás
Miranda, Leandro Andres
Resumen
The morphological development of the thyroid gland of pejerrey Odontesthes bonariensis during larval–juvenile transition was studied and related to whole-body concentrations of thyroxine (T4) and tri-iodothyronine (T3). A complementary (c)DNA fragment of the thyroid-stimulating hormone β-subunit (tshb) was sequenced and transcript levels quantified during this period. Follicles with eosinophilic and T4-immunoreactive colloids were detected at hatching together with tshb transcript levels and whole-body concentrations of T4 and T3 hormones. Thyroid follicles were located in the subpharyngeal region associated with the ventral aorta below the hyoid bone. Follicle structure switched from the rounded form at hatching to oval in juveniles. Significant increase of follicle number per larva, mean colloidal area and total colloidal area was observed throughout development with maximum values at the end of the larval–juvenile transition. A significant decrease of tshb expression together with a significant increase in T4 and T3 whole-body concentrations was observed prior to achieving the juvenile phenotype. These results are in accordance with a negative feedback regulation of tshb expression by thyroid hormones and a possible association between thyroid hormone levels and the acceleration of metabolic processes necessary to complete metamorphosis.