The role of leucine in ketogenesis in starved rats

Biochem J. 1982 May 15;204(2):399-403. doi: 10.1042/bj2040399.


The quantitative significance of the conversion in vivo of L-[U-14C]leucine to ketone bodies was determined in rats starved for 3 or 48 h. In animals starved for 3 h, 4.4% of ketone-body carbon is derived from the metabolism of leucine, and in rats starved for 48 h the corresponding value is 2.3%. This conversion occurs rapidly, and the specific radioactivity of ketone bodies in blood is maximal at 2 min after the intravenous injection of labelled leucine for both periods of starvation. The flux of leucine in the blood is 1.01 and 1.04 mumol/min per 100 g body wt. respectively for animals starved for 3 and 48 h. The specific radioactivity of blood ketone bodies was compared at 2 min after the injection of labelled leucine, lysine and phenylalanine. The specific radioactivity was 4-5 fold higher with leucine than with lysine or phenylalanine.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Ketone Bodies / biosynthesis*
  • Ketone Bodies / blood
  • Leucine / blood
  • Leucine / metabolism*
  • Phenylalanine / metabolism
  • Rats
  • Starvation / blood
  • Starvation / metabolism*
  • Time Factors


  • Ketone Bodies
  • Phenylalanine
  • Leucine