[In vivo effect of L-thyroxine on carbohydrate content of glycoproteins in subcellular fractions of the rat liver].

Effect of various doses of L-thyroxin on content of some carbohydrates (sialic acids, hexosamines, hexoses bound with proteins and L-fucose) in glycoproteins was studied in rat liver subcellular fractions. Content of these carbohydrates was altered similarly in liver tissue, whereas various doses of the hormone caused different changes of the glycoprotein components in liver tissue subcellular fractions. Within 24 days after L-thyroxin administration small doses of the hormone led to elevation of these carbohydrates in mitochondria and microsomes, while their content was unaltered in biomembranes, intermediate doses caused a decrease of the carbohydrates in mitochondria and microsomes and an increase in plasmatic mitochondrial and microsomal membranes, high doses of L-thyroxin caused a decrease of the carbohydrates in all the structures studied. Duration of normalization of the glycoprotein carbohydrate components in rat liver tissue depended on the L-thyroxin dose administered.