MIP-1 alpha is a regulator of mitotic and meiotic DNA synthesis during spermatogenesis.

To find out whether macrophage inflammatory protein-1 alpha (MIP-1 alpha) has a role in the regulation of germ cell development, we studied its effects on spermatogenic stage-specific DNA synthesis in vitro. MIP-1 alpha increased the DNA synthesis of primitive type A2-4 spermatogonia and of premeiotic cells, whereas the DNA synthesis of more differentiated intermediate and type B spermatogonia was inhibited when cultured in the presence of MIP-1 alpha. An antibody against MIP-1 alpha cross-reacted with a protein of 15 kDa from every spermatogenic stage of rat seminiferous epithelium. Immunohistochemical studies with the same antibody revealed a complex pattern of MIP-1 alpha localization both in primitive and advanced spermatogenic cells. These observations suggest that MIP-1 alpha is a local regulator of mitotic and meiotic DNA synthesis.