Dietary alteration of translatable mRNA sequences coding for rat liver pyruvate kinase.
Poly(A+) RNA (RNA containing a polyadenylic acid sequence) was isolated from individual livers of rats fed standard lab chow, fasted, or fasted and refed a high carbohydrate diet. The level of functional mRNA coding for pyruvate kinase was assayed using a rabbit reticulocyte in vitro translation system. The total 35S incorporation into newly synthesized liver pyruvate kinase was measured and compared to 35S incorporation into albumin, total trichloroacetic acid-precipitated proteins, and released polypeptide chains. The relative level of mRNA coding for liver pyruvate kinase decreases almost 60% upon fasting and increases approximately 15-fold upon refeeding with a high carbohydrate diet for 24 h. These observed changes in the amount of mRNA coding for liver pyruvate kinase agree with the previously reported changes in the relative rates of liver pyruvate kinase synthesis measured in vivo during these dietary stresses. Thus, it is suggested that the alterations in the amount of pyruvate kinase in liver in response to these dietary stresses primarily result from alteration in the amount of functional mRNA coding for the enzyme.
D000818:Animals; D004032:Diet; D004040:Dietary Carbohydrates / Q000494:pharmacology; D005215:Fasting; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008297:Male; D014176:Protein Biosynthesis / Q000187:drug effects; D011770:Pyruvate Kinase / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats
D004040:Dietary Carbohydrates; D012333:RNA, Messenger; D011770:Pyruvate Kinase