Growth regulation of astrocytes and C6 cells by TGF beta I: correlation with gap junctions

Transforming growth factor (TGF) beta l enhanced in vitro [H-3]thymidine in corporation into C6 cells and reduced that of astrocytes in the presence of a high serum concentration. It concomitantly raised the gap junction inter cellular communication (GJIC) in normal astrocytes but reduced the coupling of Cb cells, and respectively increased or decreased the proportion of P-2 -phosphorylated connexin (Cx) 43 isoform in these cells. Finally, octanol, which inhibited GJIC in both cell types, increased the thymidine incorporat ion in C6 cells, but neither altered the proliferation of astrocytes nor th eir response to TGF beta l. These data indicate that an inhibition of gap j unction intercellular communication, due to an altered phosphorylation of c onnexin 43, may contribute to the proliferative response of C6 glioblastoma cells to TGF beta l. NeuroReport 11:2837-2841 (C) 2000 Lippincott Williams & Wilkins.