Table 3.
The effect of L-glutamyl-histamine, related peptides L-Glu-Trp, Pro-Glu-Trp and Con A on [3H]-thymidine incorporation into DNA of mouse spleen lymphocytes in vitro.
| Compounds | n | c.p.m./5 × 105 cells ± s.e.m. | Stimulation index | P < |
|---|---|---|---|---|
| Control (free of mitogen or testing compound) | 7 | 796 ± 276 | ||
| Con A µg/ml | ||||
| 2·5 | 5 | 6620 ±720 | 8·3 | 0·001* |
| 5·0 | 5 | 26607 ±6689 | 33·4 | 0·01* |
| 10·0 | 4 | 49002 ±13003 | 61·6 | 0·01* |
| 25·0 | 5 | 5055 ±1167 | 6·4 | 0·01* |
| L-Glu-Hist µg/ml | ||||
| 2·5 | 4 | 6222 ±2608 | 7.8 | 0·1 |
| 5·0 | 5 | 34042 ±17765 | 42.8 | 0·1 |
| 10·0 | 6 | 33589 ±10336 | 42.2 | 0·05* |
| 25·0 | 4 | 4528 ±3293 | 5.7 | n.s. |
| L-Glu-Trp µg/ml | ||||
| 2·5 | 5 | 3184 ±346 | 4·0 | 0·001* |
| 5·0 | 4 | 29634 ±8350 | 37·2 | 0·01* |
| 10·0 | 5 | 13636 ±3501 | 17·1 | 0·01* |
| 25·0 | 5 | 1000 ±225 | 1·3 | n.s. |
| L-Pro-Glu-Trp µg/ml | ||||
| 2·5 | 6 | 2070 ±852 | 2·6 | n.s. |
| 5·0 | 5 | 2318 ±1075 | 2·9 | n.s. |
| 10·0 | 4 | 4935 ±3076 | 6·2 | n.s. |
| 25·0 | 5 | 3741 ±2405 | 4·7 | n.s. |
n = number of determinations;
*
significant differences with control; n.s.: non significant difference with control. Results are the means ± s.e.m. of three to five experiments. The data do not indicate any specific effect of L-Glu-Hist versus L-Glu-Trp, but indicate the input and important role of L-Glu residue in the structure of peptidomimetic in the signalling activity.