Rapid loss of translatable messenger RNA of phosphoenolpyruvate carboxykinase during glucose repression in liver.
The rate of synthesis of phosphoenolpyruvate carboxykinase (EC 4.1.1.32) in rat liver decreased with a half-life of 30 min after fasted rats were refed either a chow diet or glucose. A requirement for both glucose and insulin to bring about this rapid deinduction was shown, as well as the ability of dibutyryl adenosine 3':5'-cyclic monophosphate to block the decrease in enzyme synthesis. Estimates of the stability of messenger RNA of phosphoenolpyruvate carboxykinase were made by using the inhibitors actinomycin D and cordycepin to block further messenger RNA synthesis, and then measuring the decrease in specific enzyme synthesis. It is suggested that the use of actinomycin D yields an overestimation of the template stability. The results with cordycepin imply that the enzyme messenger RNA has a short half-life of approximately 1 hr. Thus, it is possible that deinduction may proceed by way of a decrease in messenger RNA production, leading to a rapid fall in the synthesis of phosphoenolpyruvate carboxykinase.
D000818:Animals; D000242:Cyclic AMP / Q000494:pharmacology; D003600:Cytosol; D003609:Dactinomycin / Q000494:pharmacology; D003839:Deoxyadenosines / Q000494:pharmacology; D003921:Diabetes Mellitus, Experimental; D004794:Enzyme Repression / Q000187:drug effects; D005215:Fasting; D005247:Feeding Behavior; D005947:Glucose / Q000494:pharmacology*; D006207:Half-Life; D007328:Insulin / Q000494:pharmacology; D008099:Liver / Q000201:enzymology*; D008297:Male; D010729:Phosphoenolpyruvate Carboxykinase (GTP) / Q000096:biosynthesis*; D011233:Precipitin Tests; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000378:metabolism; D051381:Rats; D014158:Transcription, Genetic / Q000187:drug effects
D003839:Deoxyadenosines; D007328:Insulin; D012333:RNA, Messenger; D003609:Dactinomycin; D000242:Cyclic AMP; D010729:Phosphoenolpyruvate Carboxykinase (GTP); D005947:Glucose