[RNA-metabolism in aging (author's transl)].

After intraperitoneal application of 14C-orotic acid the tracer distribution and the labelling of total RNA in different organs of two groups of Wistar rats (5 and 22,5 months old) were represented. After 60 min 2/3 of tracer were found in liver and kidney. The uptake by liver of old animals is decreased significantly. The interactions between the tracer distribution in the organism, the time related uptake by the organs, the organ function (influenced by methimazol) and the specific activity of RNA were represented. From the results the conclusion is drawn that the comparison of the specific activities of total RNA alone--especially in comparison of young with old animals--is not sufficient for the examination of RNA synthesis.