Glucose clearance and uptake is increased in the SOD1G93A mouse model of amyotrophic lateral sclerosis through an insulin-independent mechanism

Abstract

Metabolic disturbances are associated with the progression of the neurodegenerative disorder, amyotrophic lateral sclerosis (ALS), however the molecular events that drive energy imbalances in ALS are not completely understood. In this study we aimed to elucidate deficits in energy homeostasis in the SOD1G93A mouse model of ALS. We identified that SOD1G93A mice at mid-symptomatic disease stage have increased oxygen consumption and faster exogenous glucose uptake, despite presenting with normal insulin tolerance. Fasting glucose homeostasis was also disturbed, along with increased liver glycogen stores, despite elevated circulating glucagon, suggesting that glucagon signalling is impaired. Metabolic gene expression profiling of livers indicated that glucose cannot be utilised efficiently in SOD1G93A mice. Overall, we demonstrate that glucose homeostasis and uptake are altered in SOD1G93A mice, which is linked to an increase in insulin-independent glucose uptake and a disturbance in glucagon sensitivity, suggesting glucagon secretion and signalling could be potential therapeutic targets for ALS.