The antiketogenic effect of alanine in normal man: evidence for an alanine-ketone body cycle.
The effect of alanine on ketone body levels, independent of hormonal changes, in normal man has been investigated. Five normal subjects were given somatostatin infusions (200 micrograms/hour) for 3 hr. After 1 hr alanine or isotonic saline was infused for 2 hr. With saline blood beta-hydroxybutyrate and acetoacetate levels rose steadily to a peak of 0.230 plus or minus 0.053 and 0.112 plus or minus 0.023 mmole/l respectively. With alanine beta-hydroxybutyrate and acetoacetate levels plateaued at 0.099 plus or minus 0.020 and 0.055 plus or minus 0.006 mmole/l respectively. Alanine levels reached nearly 1 mmole/l but a significant effect on ketone body levels was apparent at physiologic levels (less than 0.6 mmole/l). Plasma fatty acid and glycerol levels did not change significantly. Insulin C-peptide and glucagon levels were suppressed to a similar extent in both experiments. These results support the view that alanine suppresses ketogenesis in man by a direct hepatic effect independent of insulin and glucagon. It is suggested that this forms part of a negative feedback substrate cycle between alanine and ketone bodies.
D020155:3-Hydroxybutyric Acid; D000090:Acetoacetates; D000328:Adult; D000409:Alanine; D001786:Blood Glucose / Q000378:metabolism; D002096:C-Peptide / Q000097:blood; D005934:Glucagon / Q000097:blood; D006801:Humans; D006885:Hydroxybutyrates / Q000097:blood; D007328:Insulin / Q000097:blood; D007651:Keto Acids / Q000097:blood; D007657:Ketone Bodies / Q000097:blood*; D007700:Kinetics; D008297:Male; D013004:Somatostatin
D000090:Acetoacetates; D001786:Blood Glucose; D002096:C-Peptide; D006885:Hydroxybutyrates; D007328:Insulin; D007651:Keto Acids; D007657:Ketone Bodies; C016635:acetoacetic acid; D013004:Somatostatin; D005934:Glucagon; D000409:Alanine; D020155:3-Hydroxybutyric Acid