Figure 4

Life-shortening effects of L-ornithine, L-citrulline and polyamines. A. Hypoxic flies were fed on a 10% sucrose medium supplemented with 10 mM of the indicated compounds and survivorship curves were determined. Mean longevities ± sem are shown. Sample sizes are indicated in parentheses. B, C: Dose dependent actions of L-ornithine (B) or of L-citrulline (C) on the survival of hypoxic flies. Hypoxic flies were fed on a 10% sucrose diet supplemented with the indicated concentrations of amino acids and survivorship curves were determined. The dotted lines show the survivorship curves obtained for flies fed on pure sucrose diet (blue) or under starvation conditions (red). Sample sizes are indicated in parentheses. Note that low mM concentrations of L-ornithine and L-citrulline produced near half maximum reductions in the median and maximum longevities of the flies. Survivorship curves of flies fed on 10 mM putrescine or 10 mM spermidine are presented in Figure 5 (E and F).