[Effect of thyrotoxicosis on lipid fatty acid composition in various subcellular fractions of the rat brain].

Thyrotoxicosis, which developed after subcutaneous administration of L-thyroxin at a dose of 400 micrograms/100 g of body mass, was accompanied by distinct alteration of fatty acid composition in lipids of adult rat brain myelin, synaptosomes, mitochondria and microsomes. The most significant alterations were detected in synaptosomes and mitochondria. Under conditions of thyrotoxicosis the ratio of polyunsaturated docosahexaenic and docosatetraenic acids was decreased in synaptosome lipids, whereas the content of palmitic, oleic and neuronic acids was increased. The ratio of unsaturated arachidonic and docosahexaenic fatty acids was increased but content of palmitic and linoleic acids was decreased in mitochondrial lipids.