Efeito do hipotireoidismo transitório induzido pelo 6­n­propil­2­tiouracil (PTU) sobre o testículo de rã­touro (Lithobates catesbeianus)

• Ano de defesa: 2013
• Autor(a) principal: Pacheco, Camila Mariangela
• Orientador(a): Matta, Sérgio Luis Pinto da
• Banca de defesa: Silva, Ita de Oliveira e , Matta, Ana Paula de Lima Florentino
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Biologia Animal
• Departamento: Biologia e Manejo animal
• País: BR
• Palavras-chave em Português: Espermatogênese; Rã-touro; Hormônios tireoidianos
• Palavras-chave em Inglês: Spermatogenesis; Bullfrog; Thyroid hormones
• Área do conhecimento CNPq: CNPQ::CIENCIAS BIOLOGICAS::ZOOLOGIA
• Link de acesso: http://locus.ufv.br/handle/123456789/2282

Over the past 20 years, several studies have associated the action of thyroid hormones in the testes, demonstrating that the proliferation of Sertoli cells, as well as function and steroidogenic gametogênica testis are regulated directly or indirectly by these hormones during the neonatal period.This study examined the characteristics of testicular adult bullfrogs when subjected to transient hypothyroidism induced by PTU during the larval stage. Therefore three groups of 80 tadpoles in stage 34 of Gosner were organized: the control group G1, G2 and G3 groups held for 60 days in solutions of PTU in the concentration of 75 and 150 ppm, respectively.Hypothyroidism was confirmed in tadpoles killed on the sixtieth day of treatment by observation and morphometric evaluation of the thyroid, with a significant increase in vascularization and reduced the diameter and area of the follicular lumen, while reducing the size and weight of tadpoles. To analyze the action of transient hypothyroidism in adult testes, the frogs were euthanized seven months after the end of treatment, being made analyzes biometrics body weight and snout‐vent length.In testicular morphology were analyzed, the proportion of testicular parenchyma, the number of germ cells and Sertoli cells, the ratio of the germ cell types, frequency of cysts germ, cystic tubular area and diameter and volume of the Leydig cell. The only difference observed was with respect to the testis increase the ratio of the number of secondary spermatocytes and number of cysts by Sertoli cells. In the remaining parameters were not significant differences. It is understood that the effects of hypothyroidism are reversible in larval frogs, tadpoles because the G2 and G3, which showed smaller changes in thyroid weight and regained weight and size in adulthood.