A dual effect of somatostatin on the proliferation of cultured rat mesangial cells.

The present experiments were designed to analyze the ability of somatostatin to modulate the proliferation of cultured rat mesangial cells. In the absence of fetal calf serum, somatostatin stimulated cell proliferation in a dose-dependent manner. In contrast, in proliferating cells, somatostatin inhibited cell proliferation, also in a dose-dependent fashion. Zaprinast, a rather specific cyclic GMP phosphodiesterase blocker, inhibited the somatostatin-dependent proliferation in the absence of growth factors. However, it potentiated the inhibitory effect on proliferating cells. These results support a dual role for somatostatin in the regulation of mesangial cell proliferation. The inhibitory effect of the peptide may be mediated by cyclic GMP.