title: [Metabolism of poly(A+)mRNA during ontogenesis: changes in half-life and processing time in rat brain cortical cells].
abstract: The values of half-life (t 1/2) and processing (to) time of poly(A+) mRNA were calculated from the kinetics of label accumulation by free and membrane-bound polyribosomes of brain cortical cells of 1-, 7-, 30-, 180-, 360-, 540-, and 720-day-old rats and of 17- and 21-day-old embryos. The membrane-bound polyribosomes contain only one class of poly(A+) mRNA, whereas the free ones--predominantly two classes. The most pronounced changes in poly(A+) mRNA metabolism are observed in the case of free polyribosomes. It was found that poly(A+) mRNA of both polyribosomal classes is generally stabilized during late embryogenesis and neonatal period, after which the values of t 1/2 are decreased, showing a drastic fall upon ageing. The changes in to are inversely related to those of t 1/2. Free polyribosomes, beginning with the 30th postnatal day, reveal a short-living rapidly turned over  poly(A+) mRNA, whose parameters remain practically unchanged throughout the ontogenesis period under study.
mesh_terms: D000375:Aging; D000818:Animals; D002540:Cerebral Cortex / Q000254:growth & development* / Q000378:metabolism; D006207:Half-Life; D007700:Kinetics; D008297:Male; D008433:Mathematics; D011061:Poly A / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats
chemical_list: D012333:RNA, Messenger; D011061:Poly A
vernacular_title: Metabolism poli(A+) mRNK v ontogeneze: izmeneniia vremen poluzhizni i protsessinga v kletkakh kory golovnogo mozga krys.