Serum Ketone Body Levels and Acetoacetate/β-Hydroxybutyrate Ratio in Hypoxia

Abstract

The effect of hypoxia on serum ketone body levels was studied in rats and cultured hepatocytes. When rats inhaled a gas-mixture composed of 25% air in N₂, the sum of their ketone bodies (β-hydroxybutyrate plus acetoacetate) increased gradually after 2 hour, reaching 293% of the original level after 4 hour. The acetoacetate/β-hydroxybutyrate ratio decreased appreciably from 0.58 to 0.28 in the same 4 hour period. In cultured rat hepatocytes, the ketone-body ratio also decreased with lowering oxygen tension. However, the exposure of the cells to hypoxia depressed the accumulation of ketone-bodies, indicating that the increase in the sum of serum ketone bodies induced by the exposure of rats to hypoxia was due to a decrease in their utilization in extrahepatic tissues. The determination of the sum of ketone bodies and of the ketone body ratio provides valuable information for the severity and diagnosis of hypoxia due to diminished lung function.