info:eu-repo/semantics/article
Differences in responsiveness and sensitivity to exogenous disruptors of the thyroid gland in three anuran species
Fecha
2019-11Registro en:
Fabrezi, Marissa; Lozano, Verónica Laura; Cruz, Julio César; Differences in responsiveness and sensitivity to exogenous disruptors of the thyroid gland in three anuran species; Wiley-liss, div John Wiley & Sons Inc.; Journal Of Experimental Zoology Part B-molecular And Developmental Evolution; 332; 7; 11-2019; 279-293
1552-5007
CONICET Digital
CONICET
Autor
Fabrezi, Marissa
Lozano, Verónica Laura
Cruz, Julio César
Resumen
Anuran larval development comprises tissues/organs/systems that are: exclusively of larvae, able to be remodelled, and those of postmetamorphic stages. Also, the anuran larval development is characterized by inter-related parameters: time, size and shape forming part of growth and differentiation. The anuran metamorphosis starts when growth and differentiation achieve a threshold that differs among species since it is regulated by a number of external (environmental) and internal (hormonal) processes. Here we explore the consequences of exogenous disruptors on the thyroid gland (e.g., methimazole and thyroxine as T4) of three species by immersing premetamorphic tadpoles in predetermined concentrations of the disruptors for short periods (10 or 16 days). The species were Pleurodema borellii, Leptodactylus chaquensis, and Dermatonotus muelleri, which all breed in small temporary ponds during the summer, but differ in their ecomorphology. The experiments were conducted to evaluate the effects of these substances on larval development (based in Gosner larval stages), morphometric variation in body parameters (snout-vent and total length by larval stages), and thyroid gland histopathology at the end of the assays. In P. borelli and L. chaquensis, methimazole produces significant increment of size measurements (nonparametric Kruskal–Wallis, p <.05) during stages of digit differentiation and induced thyroid gland hypertrophy. In the three species, T4 exposure accelerated limb development and caused atrophy of thyroid gland. Prolonged T4 exposure in L. chaquensis and D. muelleri triggered metamorphic transformation in the gut and skull cartilages. Discussion about interspecific differences in responsiveness and sensitivity elucidates the importance of hormonal signals to morphological evolution.