Table 1 Intervention in the ornithine cycle and the CMX-related cytotoxicity

From: Changes in the ornithine cycle following ionising radiation cause a cytotoxic conditioning of the culture medium of H35 hepatoma cells

Modification to CMX

Arginine (m M)

Ornithine (m M)

Citrulline (m M)

NH3 (m M)

Number of test cells after 72 h

None

1.05

1.17

0.50

3.85

0.46 (4.52)a

Norvaline

2.87

0.07

0.04

1.26

2.88 (3.12)a

L15-arg

0.006

0.20

0.06

1.55

4.64 (none)a

Citrulline

Nil

0.39

1.15

1.96

3.68 (4.79)a

  1. aThe number of test cells at 72 h (106 cells) in the same media, but preincubated for 96 h without cells. Concentrations of citrulline (in arginine-deficient medium L15-arg) and of norvaline were 1 and 20 mM, respectively.
  2. CMX of different compositions from 50 000 cells (8 Gy, 96 h) was tested for its growth-promoting capacity or analysed for ammonia and the ornithine cycle compounds.
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