Rapid, transient drop in brain glucose after intravenous phloretin or 3-0-methyl-D-glucose.
Rats were injected intravenously with either phloretin (100 mg/kg) or 3-0-methyl glucose (2 g/kg) to reduce the carrier-mediated flux of glucose into brain. Plasma glucose and brain free glucose (BFG), lactate, and glycogen were measured over a 16 min time course. Injection of these substances caused a rapid drop in BFG to 60% of control at one minute and a minimum (50% of control values) at 4 min., followed by a gradual rise to control levels at 16 min. While plasma glucose fell, and then increased after injection, brain lactate and glycogen content was unaffected. Repeated injections of phloretin eventually caused a drop in brain glycogen; but with either competitor, BFG never fell below 50% of normal values. The i.v. injection of the glucose analog, 3-0-methyl glucose (the less toxic of the two drugs) is proposed as a possible means of cutting off the potentially hazardous supply of blood glucose to the postischemic brain.
D019325:3-O-Methylglucose; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D001923:Brain Chemistry; D005947:Glucose / Q000032:analysis / Q000378:metabolism*; D007275:Injections, Intravenous; D008297:Male; D008757:Methylglucosides / Q000008:administration & dosage*; D008759:Methylglycosides / Q000008:administration & dosage*; D010693:Phloretin / Q000008:administration & dosage*; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
D001786:Blood Glucose; D008757:Methylglucosides; D008759:Methylglycosides; D019325:3-O-Methylglucose; D005947:Glucose; D010693:Phloretin