Uridine phosphorylase activity during postnatal development of the rat heart.
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.
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*
D009124:Muscle Proteins; D004247:DNA; D010430:Pentosyltransferases; D014543:Uridine Phosphorylase