title: [Change in the tricarboxylic acid cycle dehydrogenase activity under the action of thyroxine in the brain of animals of varying age].
abstract: The effect of thyroxin on the activities of tricarboxylic acid cycle enzymes and NADP-malate dehydrogenase in the rat brain was studied. Experiments were conducted on 20- and 40-day old and on adult rats. Injection of L-thyroxin (50 microgram/100 g body weight) to thyroidectomized rats induced some changes in the activities of citrate-syntase, dehydrogeases of TAC and malic enzymes in the mitochondrial and cytoplasmic fractions of the brain. The most significant effect of the hormone was found in the brain of 20-day old rats there was an increase of the enzyme activities by 40--60%. The effect of the hormone on the enzymes activities could be prevented by simultaneous administration of actinomycin D (10 microgram intracerebrally). This fact indicates that the main mechanism in increasing the enzymic activity lies, probably, in stimulation of the enzyme biosynthesis by the hormone.
mesh_terms: D000375:Aging / Q000187:drug effects*; D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000201:enzymology; D002952:Citric Acid Cycle / Q000187:drug effects*; D003593:Cytoplasm / Q000201:enzymology; D004789:Enzyme Activation / Q000187:drug effects; D008928:Mitochondria / Q000201:enzymology; D010088:Oxidoreductases / Q000378:metabolism*; D051381:Rats; D013965:Thyroidectomy; D013974:Thyroxine / Q000494:pharmacology*
chemical_list: D010088:Oxidoreductases; D013974:Thyroxine
vernacular_title: Izmenenie aktivnosti degidrogenaz tsikla trikarbonovykh kislot pod deĭstviem tiroksina v mozge zhivotnykh raznogo vozrasta.