Porcine Malignant Hyperthermia. Vii: Hepatic Metabolism

Abstract

Hepatic metabolism during porcine malignant hyperthermia (MH) was investigated in seven Pietrain pigs. The estimated hepatic blood flow decreased during MH, but an increase in oxygen extraction enabled the splanchnic oxygen uptake to be maintained. There was a large release of glucose and potassium from the liver in MH which made an important contribution to the hyperglycaemia and hyperkalaemia. Measurement of hepatic uptake of the precursors of gluconeogenesis, lactate, glycerol and alanine, showed that glucose efflux from liver was derived mainly from glycogenolysis. Lactate uptake by the liver increased during MH, and there was no evidence of hepatic lactate production during the profound acidosis as suggested by in vitro studies with the isolated liver. There was no evidence of major abnormality of hepatic function during porcine MH.

Effects of MDMA on blood glucose levels and brain glucose metabolism

“…Malignant hyperthermia has been previously associated with hyperglycaemia. Several works regarding hepatic metabolism during porcine malignant hyperthermia have shown a large release of glucose and potassium from the liver [45,46]. The hypoglycaemia detected in our study may have been due to severe acute hepatotoxicity induced by MDMA, suggesting that the liver could be more sensitive to MDMA at higher temperatures.…”

Proteomic changes to the sarcoplasmic fraction of predominantly red or white muscle following acute heat stress

“…For example, Zhang et al [13] observed an increase in lactate production and pyruvate kinase activity in muscle from chronically heat stressed broilers, evidence for increased glycolytic capacity. In agreement, plasma lactate concentrations rise during exercise in the heat [14][15][16], porcine malignant hyperthermia [9], and heat stressed growing steers [17]. This presumably stems from skeletal muscle efflux, but an increase in muscle lactate production and efflux is not the result of reduced muscle blood or oxygen flow [18].…”

“…Even brief bouts of heat stress can result in reduced pig performance and body weight [6]. It is also clear that skeletal muscle catabolism is increased during heat stress, as numerous studies have reported increased plasma markers of muscle breakdown in several species [7][8][9][10][11][12].…”

Portal Vein Perfusion of the Isolated Rat Liver: Some Markers of Hyperthermic Liver Damage

“…This is largely due to release of potassium and glucose from the liver (Hall et al, 1980). In this study increased potassium loss occurred during hyperthermia.…”