Insulin-induced hypoglycemia stimulates gluconeogenesis from ¹⁴C-lactate independently of glucagon and adrenaline releases in rats

Summary

Correlation between blood glucose, glucagon and adrenaline levels and gluconeogenesis was studied during the recovery from insulin-induced hypoglycemia in rats. Rats, overnight fasted, were intravenously injected with 40 µCi/kg of [U-¹⁴C]-lactate and 1 U/kg of porcine insulin under an anesthesia with pentobarbital sodium. Blood samples were drawn via the peripheral vein at 0, 5, 10 and 20 min. Plasma insulin level was 617 ±115 µU/ml at 5 min. Plasma glucose level was significantly decreased at 5 min (2.7 ± 0.3 mM at 5 min v.s. 4.3 ± 0.2 mM at 0 min, P<0.01). Plasma glucagon and adrenaline did not significantly respond at 5 min, and then rised. Specific radioactivity of plasma [l-¹⁴C]-glucose was significantly higher at 5 and 10 min in the insulin-injected rat than the saline-injected rat (204 ± 32 v.s. 130 ± 14 d.p.m./µmol at 5 min, P<0.01; 275 ± 34 v.s. 186 ± 16 d.p.m./µmol at 10 minm P<0.01). These results suggest that lowering of blood glucose level stimulates gluconeogenesis independently of the release of counter-regulatory hormones in insulin-induced hypoglycemia.

Key words

Gluconeogenesis - Lactate - Hypoglycemia