DISTINCT ROLES OF ONCOSTATIN-M AND LEUKEMIA INHIBITORY FACTOR IN THE DEVELOPMENT OF PRIMORDIAL GERM-CELLS AND SERTOLI CELLS IN MICE

Leukemia inhibitory factor (LIF) stimulates the growth of primordial g erm cells (PGCs) in mouse embryo. However, as neither mice lacking LIF nor mice lacking the LH receptor show defects in PGC growth, an alter nate cytokine for PGC growth has been postulated. We investigated the role of mouse oncostatin M (mOSM), which is structurally and functiona lly related to LIF, in germ cell development. While LIF enhanced the s urvival of migratory as well as postmigratory PGCs, mOSM acted only on the postmigratory PGCs. Consistent with its biological activity, mOSM was found to be expressed in developing gonads. In the male, Sertoli cells in neonatal testis express mOSM; however, its expression is down regulated in adult testes. Moreover, mOSM enhanced the proliferation o f Sertoli cells derived from neonatal testes in vitro more than human OSM or LIF. In contrast, postnatal ovaries do not express mOSM. These results indicate that mOSM is a stage- and sex-specific autocrine grow th factor for Sertoli cells. (C) 1998 Academic Press.