Leukaemia inhibitory factor stimulates proliferation of prospermatogonial stem cells

The effect of leukaemia inhibitory factor (LIF) on the proliferation of prospermatogonial stem cells was tested in vitro. Pieces of 3-day-old rat testis were cultured in the presence of a range of doses of LIF alone or in combination with 1 ng mL(-1) seminiferous growth factor (SGF). Stimulation of the proliferative activity of quiescent prospermatogonia was detected immunocytochemically with a cell proliferation kit. After 24 h culture, LIF significantly increased the percentage of labelled prospermatogonia, with the peak of activity at 20 pg mL(-1). The combination of LIF and SGF resulted in a decrease in DNA synthetic activity of the germ cells. Hence, LIF and SGF play a role in local regulation at the onset of spermatogenesis in the rat testis.