Effects of leukaemia inhibitory factor and other cytokines on murine and human myoblast proliferation.

It has been shown previously that leukaemia inhibitory factor (LIF) and transforming growth factor-alpha (TGF-alpha) stimulate proliferation of primary cultures of murine myoblasts. We now show that human myoblasts respond in a similar manner to LIF and TGF-alpha. These responses occur over a range of growth conditions. There are total additive effects in both human and murine myoblasts between LIF and TGF-alpha and LIF and fibroblast growth factor-beta (FGF-beta), but not between LIF and interleukin-6 (IL-6) or insulin-like growth factor 1 (IGF-1). The LIF response is initiated by a short exposure to the cytokine and is maintained for prolonged periods in its absence.