RESUMEN
Male rats subjected to surgicl thyroidectomy showed alteration in the content of fatty acids (FA) of plasma and mitochondria of liver and brain lipids in comparison to control animals (sham-operated). Those alterations depend of the kind of dietary fat intake. Control and thyroidectomized rats fed an n-6 polyunsaturated fatty acid (PUFA)-rich diet A or an n-3 PUFA-rich diet B. Thyroidectomy, independently of kind of diet, did not cause any alteration on the P/S ratio in plasma or brain mithocondria. However, it caused an increase on the P/S ratio in liver mithochondria, more evident in the dietary group B. This fact may suggest that the absence of thyroid hormones would induce a higher incorporation of PUFAs in liver lipids. Thyroidectomy caused a decrease of linoleic acid (LA) content in plasma of both dietary groups but it caused an increase of LA in diet A brain mitochondria groups. The plasma FA content, although depends on the source of fat intake, was not a mere reflection of the diet FA ingested. As the thyroidectomy also changed the content of plasma FA, it is possible to postulate that the plasma FA should be actually a reflection of the FA content of endogenous lipds