Brain glycogen supercompensation after different conditions of induced hypoglycemia and sustained swimming in rainbow trout ( Oncorhynchus mykiss )

Glycogen Supercompensation in the Rat Brain After Acute Hypoglycemia is Independent of Glucose Levels During Recovery

“…Evidence supporting this post-hypoglycemia supercompensation has been reported in the human [12,16], rat [9,14], mouse [10] and rainbow trout [15]. However, the re-establishment of glycogen content in the brain after hypoglycaemia has been involved in controversy: (1) not all studies confirmed glycogen supercompensation after acute hypoglycaemia [11], (2) there have been reports suggesting that repeated hypoglycaemia does not result in increased glycogen levels [11,16,17], and (3) patients with type 1 diabetes and hypoglycaemia unawareness display brain glycogen levels similar to those in healthy subjects [18].…”

“…Brain glycogen is hydrolysed to support energy metabolism and aid preserving neuronal function during hypoglycaemia [9][10][11][12][13][14][15]. Evidence supporting this post-hypoglycemia supercompensation has been reported in the human [12,16], rat [9,14], mouse [10] and rainbow trout [15].…”

Cerebral glycogen in humans following acute and recurrent hypoglycemia: Implications on a role in hypoglycemia unawareness

“…Another common observation in these studies is the transient nature of glycogen supercompensation. 11,12,14 Importantly, the level of glycogen supercompensation appears dependent on the intensity of the metabolic stress and how much glycogen is mobilized during the metabolic insult: Thus, glycogen supercompensation occurred only after prolonged, but not after short, fasting in the rainbow trout. 12 Consistently, the percentage of brain glycogen supercompensation after exhaustive exercise positively correlated with the percentage of glycogen decrease noted during exercise across different brain regions in rats.…”

“…Namely, brain glycogen was found to be supercompensated in rats following transient ischemia, transient hypoglycemic coma, and methionine sulfoximine induced seizures, 26 in rats subjected to transient systemic hypoxia, 27 in rats after transient neuroglucopenia upon intracerebroventricular injection of 2-deoxy-D-glucose, 13 in mice recovering from hypoglycemia, 11 in rats after exhaustive exercise, 14 and in the rainbow trout after hypoglycemia induced by prolonged fasting. 12 In addition, a 13 C MRS study indicated glycogen supercompensation in the rat brain following insulin-induced hypoglycemia. 7 In the one study where brain glycogen supercompensation was not detected after acute and recurrent hypoglycemia, 10 brain glucose levels were not restored after insulin-induced hypoglycemia, as was done in all other studies that detected glycogen supercompensation in the brain.…”

“…7,8 Consistently, glycogen is mobilized to support cerebral energy metabolism during hypoglycemia in rodents, 7,9–11 humans, 8 and lower vertebrates. 12 Furthermore, evidence indicating brain glycogen supercompensation was reported following systemic hypoglycemia in rodents, 7,11 lower vertebrates, 12 and humans, 8 after recurrent 2-deoxy-D-glucose-induced neuroglucopenia in rats 13 and after prolonged exercise in rats. 14 Note however that not all studies confirmed glycogen supercompensation following acute and recurrent hypoglycemia.…”