Effect of the thyroidectomy on male rats fed two antagonist lipid diets: I. Physiological aspects

RESUMO

Male rats fed an n-6 polyunsaturated fatty acid (PUFA)-rich diet A or an n-3 PUFA-rich diet B were subjected to a surgical thyroidectomy or to a sham-operation (control animals). Thyroidectomy caused a lesser daily increase of body weight in both dietary groups. The diet A rats showed in average greater values of body weight than diet B rats, for control and thyroidectomized animals. After 30 days of experiment thyroidectomy caused no effect on the relative weight (g/100g body weight) of liver in both dietary groups. However, it increased the relative weight) of gastrocnemius (p<0.05) and brain (p<0.001) in both dietary groups, and it decreased the relative weight of heart in both dietary groups, and it decreased the relative weight of heart in diet A (NS) and in diet B (p<0.05) groups. The relative weights of heart, gastrocnemius, liver and brain of control and thyroidectomized rats of diet A groups were lower than respective organs of diet B groups. Thyroidectomy did not affect the level of plasma proteins of diet B rats was higher than diet A rats, for controls or thyroidectomized animals. Iodine uptake by thyroid gland, the plasma level of T3 of diet B control rats were significant higher thand diet A control rats, but the plasma level of T4 of diet A control rats was higher than diet B control rats (NS). These results suggested that the thyroidectomy and or lipid diets may alter the rat development as well the ingestion of antagonist lipid diets may alter thyroid gland functions