[Effect of hypothyroidism on the solid form of Ehrlich tumor in intact or castrated adult female mice]. / Efeito do hipotireoidismo no tumor de Ehrlich sólido em camundongos fêmeas castradas e não castradas.

The effect of hypothyroidism on the solid form of the Ehrlich tumor in intact or castrated adult female mice was studied. Hypothyroidism was induced by treatment with propylthiouracil (PTU). Forty mice were divided into four groups: castrated hypothyroid, intact hypothyroid, castrated euthyroid, and intact euthyroid. The mice were inoculated with suspension cells into the left footpad. The tumor growth curve was determined by measuring the inoculated footpad during 12 days. At the end of the experimental period the mice were sacrificed. Hypothyroidism was associated with a reduction in size of the tumor only in the castrated animals. Although the neoplastic growth was lower, mean nuclear diameter, number of nucleolar organizer regions (NORs), and area of mitosis were higher. In conclusion, hypothyroidism resulted in a delayed growth of the tumor, but it did not affect the malignant features of the neoplastic cells. In addition, the isolated effect of castration caused only mild alterations, whereas hypothyroidism associated with castration resulted in a more prominent delay in the growth rate of the Ehrlich tumor.

Efeito do hipotireoidismo no tumor de Ehrlich sólido em camundongos fêmeas castradas e não castradas / Effect of hypothyroidism on the solid form of the Ehrlich tumor in intact or castrated adult female mice

Foi estudado o efeito do hipotireoidismo, induzido pelo propiltiouracil (PTU), no tumor de Ehrlich sólido, implantado em camundongos fêmeas adultas castradas ou não. Foram utilizados 40 animais distribuídos em quatro grupos: hipotireóideo castrado, hipotireóideo não castrado, eutireóideo castrado e eutireóideo não castrado. Os animais receberam uma injeção de células neoplásicas no coxim plantar esquerdo. A curva de crescimento tumoral foi determinada por mensurações da pata inoculada durante 12 dias quando os animais foram necropsiados. A hipofunção tireoidiana reduziu o tamanho do tumor de Ehrlich nos animais castrados. Embora o crescimento neoplásico tenha sido menor, o diâmetro nuclear médio e o número de regiões organizadoras de nucléolos (NORs) e de mitoses/campo foram maiores. Conclui-se que o hipotireoidismo retarda o crescimento do tumor de Ehrlich sólido, sem alterar as características celulares de malignidade, que o efeito isolado da castração causa alterações discretas e que a associação hipotireoidismo-castração potencializa o retardo do crescimento do tumor de Ehrlich sólido.