title: Uridine phosphorylase activity during postnatal development of the rat heart.
abstract: Uridine phosphorylase activity was assayed in heart extracts from rats of different postnatal age. Activity was low at birth, increased to a maximum at 8--14 days of postnatal development and then decreased to a low adult level. The switch from cellular hyperplasia to hypertrophy determined by the ratio proteins/DNA occurred at day 18 of development. It is suggested that the activation of uridine phosphorylase activity during the early life of the rat may be a critical element of the onset of hypertrophy.
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D004247:DNA / Q000032:analysis; D006321:Heart / Q000254:growth & development*; D009124:Muscle Proteins / Q000032:analysis; D009206:Myocardium / Q000201:enzymology; D010430:Pentosyltransferases / Q000378:metabolism*; D051381:Rats; D014543:Uridine Phosphorylase / Q000378:metabolism*
chemical_list: D009124:Muscle Proteins; D004247:DNA; D010430:Pentosyltransferases; D014543:Uridine Phosphorylase