Aim: To investigate the effects of IL-2 on the proliferation, cell cycle, protein kinase C(PKC) and cAMP/cGMP of cultured human pituitary adenoma cells.
Methods: MTT colorimetry, (3)H-TdR and flow cytometry were used to detect the proliferation and radioimmunoassay was used to observe the effect of IL-2 on PKC activity and cAMP/cGMP levels of cultured human pituitary adenoma cells.
Results: (1) IL-2 (1 x 10(4), 1 x 10(5) and 5 x 10(5) U/L) stimulated the proliferation and DNA synthesis of cultured human pituitary adenoma cells in a dose-dependent manner. (2) IL-2 (1 x 10(4), 1 x 10(5) and 5 x 10(5) U/L) decreased the ratio of pituitary adenoma cells in G(1) phase and increased the ratio in S and G(2) phase markedly. (3) Compared with control, PMA, a PKC activator, increased the activity of membrane and total PKC in human pituitary adenoma cells. However, after treatment with IL-2 (1 x 10(5) U/L), a significant increase of the activity of cytoplasmic, membrane and total PKC in human pituitary adenoma cells was observed. (4) IL-2 (5 x 10(4), 1 x 10(5) U/L) decreased the amount of cAMP in the cytoplasm of human pituitary adenoma cells, but had no effect on that of cGMP.
Conclusion: IL-2 can stimulate the proliferation of pituitary adenoma cells through PKC and cAMP/cGMP signaling pathways.