[Peculiarities of urea distribution in tissues of rats of different age].
The content of urea was studied in protein-free filtrates of the liver kidneys, skeletal muscles, myocardium, spleen, brain tissues and blood serum as well as in urine of 1, 3, 6, 12 and 24-month rats. It is shown that at the age of 6 months the content of urine in most tissues under study is significantly decreased (by 42-73%), at the age of 12 months in the spleen and at the age of 24 months in the brain tissues as compared to the one-month animals. The level of urine decrease in the liver and brain tissues of 24-month animals is less pronounced than in other tissues, that corresponds to age peculiarities of their protein metabolism. A decrease of blood consumption per weight unit and a relative increase in the amount of nitrogen excreted with urine are observed with ageing. The arginase activity in the liver decreases essentially only in 3-month animals. A conclusion is drawn that peculiarities of food consumption and the character of changes in the urea content in tissues and urine are adaptation manifestation of an age decrease in the intensity of nitrogen metabolism and protein demand of the organism.
D000375:Aging; D000818:Animals; D001921:Brain / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D009132:Muscles / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism; D051381:Rats; D013154:Spleen / Q000378:metabolism; D014018:Tissue Distribution; D014508:Urea / Q000378:metabolism*
D014508:Urea
Osobennosti raspredeleniia mocheviny v tkaniakh krys raznogo vozrasta.