The effect of buformin upon blood glucose level of normal rats and carbohydrate metabolism of the isolated rat diaphragm

Abstract

1. 2 h after a single oral dose of 25 mg of buformin per normal rat, the blood glucose level was significantly lower when compared to the control group (78,9 4-1.4 rag/100 ml to 67.1 4-5.2 rag/100 ml, p < 0.05). The incubated diaphragms of these animals showed no differences with regard to glucose uptake, lactate produetion and glucose oxidation in comparison to the control.-2. When treated for 7 days with identical dosages of buformin the blood glucose level of the treated rats was lowered to a greater extent (80.5 4-3.7 rag/100 ml to 51.6 4-5.7 rag/100 ml, p < 0.01) and the incubated diaphragms showed a significantly increased glucose uptake, lactate production and decreased glucose oxidation.-3. As a result of these findings and supported by reports in literature it is suggested that the drug may accumulate in the skeletal muscle of normal rats.-4. No insulin potentiating effect could be detected.-5. With regard to previous reported results from our laboratory we suggest that bignanides may increase Cori cycle activity in the rat. tigung kiirzlich yon uns mitgeteilter Bcfunde aus in vivo-Untersuchungen an normalen l~atten, die ergaben, dal~ nach mehrt~giger oraler Vorbchandlung mit 25 mg Buformln der Einbau yon Radioglueose in das Zwerchfellglykogen und der Glykogengehalt selbst erh6ht waren, erschcint es mSglich, dab Biguanide im Skeletmuskel normaler I~atten die Aktivitiit des Cori Cyelus stimulieren.

Das isoliert perfundierte Hinterbein der Ratte als Modell zur Untersuchung des Muskelstoffwechsels

“…Fiir Untersuchungen des Stoffwechsels der peripheren Muskulatur und dessen Beeinflussung durch Hormone oder pharmakologisch wirksame Substanzen [28] ist es besonders wiinschenswert, ein den in vivoBedingungen (anatomisch wie auch physiologisch) mSglichst identisches Modell zu haben. Sowohl das isolierte inkubierte als auch das perfundierte Rattenzwerchfell erfiillen nur sehr begrenzt diese Bedingungen [24].…”

Effect of phenformin on substrate metabolism of working muscle in maturity onset diabetics

“…Conflicting results, however, have been obtained on peripheral glucose oxidation [12,13] in relation to the development of lactic acidosis during biguanide treatment. Using the forearm method decreased lactate release by resting muscle was found in healthy volunteers [14]; in contrast, in vitro studies showed increased muscle lactate output [15][16][17][18]. Similarly, peripheral glucose uptake which was found to be lessened in healthy man [14], was unchanged [19] or increased [20] in maturity onset diabetics.…”