title: Rat liver uridine diphosphate glucose dehydrogenase: dual mechanism of regulation in vivo.
abstract: Rat liver UDPglucose (UDPG) dehydrogenase activity was observed to be decreased after fasting and could be restored to normal levels after refeeding glucose. This could be prevented by prior injection of puromycin, suggesting de novo protein synthesis. Administration of insulin to normal rats on stock diet did not influence the enzyme activity. However, the enzyme activity was decreased in the diabetic condition. Intraperitoneal injection of insulin caused an enhancement of the enzyme activity in diabetic animals. Hepatic UDPG dehydrogenase activity was observed to be decreased on ascorbic acid feeding or intraperitoneal injection of the same. The intraperitoneal injection of either insulin or cAMP to ascorbic acid-treated rats resulted in an increase in enzyme activity reaching normal levels. The insulin-mediated increase could not be prevented by prior injection of puromycin, suggesting a post-translational effect. These results indicate two distinct mechanisms for in vivo regulation of hepatic UDPG dehydrogenase.
mesh_terms: D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology; D002237:Carbohydrate Dehydrogenases / Q000378:metabolism*; D000242:Cyclic AMP / Q000494:pharmacology; D003921:Diabetes Mellitus, Experimental / Q000201:enzymology; D004032:Diet; D005215:Fasting; D005502:Food; D005947:Glucose / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology; D008099:Liver / Q000201:enzymology*; D008297:Male; D011691:Puromycin / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D014533:Uridine Diphosphate Glucose Dehydrogenase / Q000378:metabolism*
chemical_list: D007328:Insulin; D011691:Puromycin; D000242:Cyclic AMP; D002237:Carbohydrate Dehydrogenases; D014533:Uridine Diphosphate Glucose Dehydrogenase; D005947:Glucose; D001205:Ascorbic Acid