In vitro biosynthesis of rat sperm outer dense fiber components

Conditions were established for in vitro culture of seminiferous tubules of adult rat testis. Tubules fragments were able to incorporate radioactive amino acids for up to 6 hours of incubation at 32 degrees C in a modified Eagle's minimum media, indicating biosynthetic activity. Addition of D-glucose (11 Mm) increased the incorporation of either [3H] Leucine or [35S] Methionine four-fold in the protein components of seminiferous tubules. Polyclonal antibodies against outer dense fibers (ODF) polypeptides, which represent approximately 30% of the total sperm proteins, immunoprecipitated 5% of the total radioactivity from cultures carried out either in the presence or absence of D-glucose. Moreover, antibodies specific for the 27-30 kilodalton polypeptides of ODF immunoprecipitated 2% of the total radioactivity, showing no differences in the presence and absence of D-glucose. This study indicates that ODF polypeptides can be synthesized in vitro at 32 degrees C with and without D-glucose.