Effects of Glucagon on Basal Metabolic Rate and Oxidative Phosphorylation of Rat Liver Mitochondria

Summary

Glucagon produced fast but transient stimulation of respiration rates in state 3 and state 4 rat liver mitochondria when either succinate or β-hydroxybutyrate was used as substrate. Stimulation was already detectable 7.5 minutes after glucagon injection. Glucagon also clearly activated basal metabolic rate, and its effects on oxygen consumption rates reached their maximum 20 to 30 minutes after injection. Pretreatment with cycloheximide blocked most activation by glucagon of both oxidative phosphorylation and basal metabolic rate, but did not affect its enhancement of glycaemia. The rise in basal metabolic rate was the direct result of glucagon's effect on mitochondria, which was secondary to nucleocytoplasmic protein synthesis.

Key-Words:

Glucagon - Basal Metabolic Rate - Rat Liver Mitochondria - Oxidative Phosphorylation - Glycaemia