Regulation of mucosal phosphofructokinase in the small intestine of the streptozotocin-diabetic rat.
The total activity of mucosal phosphofructokinase in the proximal jejunum of the streptozotocin-diabetic at was found to be diminished compared with normal from 13.4 to 10.4 units/g wet weight, mucosa and the activity ratio of the enzyme at pH 7 was diminished from 0.40 to 0.23, indicating that the enzyme is more susceptible to inhibition by ATP. The combination of these changes is, in principle, more than sufficient to account for the 29% decrease in glucose utilisation observed in the jejunum of diabetic rats. Insulin, when injected in vivo, has the ability to restore both the total activity and the regulatory properties of phosphofructokinase to normal in streptozotocin-diabetic rats. The action of insulin is blocked by the protein synthesis inhibitor cycloheximide, and is not mediated by changes in blood glucose levels.
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D003513:Cycloheximide / Q000494:pharmacology; D003921:Diabetes Mellitus, Experimental / Q000201:enzymology*; D005260:Female; D007328:Insulin / Q000494:pharmacology; D007413:Intestinal Mucosa / Q000201:enzymology*; D007421:Intestine, Small / Q000201:enzymology*; D007583:Jejunum / Q000201:enzymology; D010732:Phosphofructokinase-1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D007328:Insulin; D000255:Adenosine Triphosphate; D003513:Cycloheximide; D010732:Phosphofructokinase-1