Thyroid function in diabetic rats by the administration of streptozotocin.

Abstract

Para estudiar las variaciones de la funci6n tiroidea en ratas diabeticas, ratas mantenidas con una dieta pobre en yodo se inyectaron con estreptozotocin y fueron comparadas con controles inyectadas con el medic y alimentadas con la misma dieta. Las ratas tratadas con estreptozotocin mostraron una intensa diuresis e hiperglucemia durante los 29 dias despues del tratamiento. Estes animales presentaban una concentraci6n normal de 127PBI plasmatico, pero una captaci6n tiroidea de 13'1 y una concentraci6n de 131PBI plasmatico, reducidas a las 24 horas de la inyecci6n del trazador. Los animales tratados con estreptozotocin mostraron un elevado contenido en 1271 en sus tiroides y una alterada distribuci6n porcentual de iodoaminoacidos en la glandula, con una aumentada proporci6n de DIT y una disminuida proporci6n de r. y T,. Los resultados permiten sugerirque la sintesis y secreci6n de las hormonas tiroideas se encuentran reducidas en los animales diabeticos. Esta disminuida tunci6n tiroidea concuerda con la disminuida efectividad hormonal del TSH descrita por otros autores

To study the changes in the thyroid function in diabetic rats, streptozotocin was injected i.p. in rats on a low iodine diet. They were compared with controls which were fed the same diet and injected with medium. The streptozotocin treated animals showed an intense diuresis and hyperglycemia during the 29 days after the treatment. These animals-had a normal plasma 127PBI concentration but reduced uptake of 131 1 by their thyroids and plasma concentration 24 hours after the injection of the tracer. The rats treated with streptozotocin showed an increased content of 1271 in their thyroids and an altered distribution of the percentages of radioactive iodoaminoacids, with an augmented proportion of DIT and reduced concentrations of T4 and T3 • These results suggest that the synthesis and release of thyroid hormones are reduced in the diabetic animals. This decreased thyroid function agrees with the reduced hormonal effectiveness of TSH described by other authors.