[Identification of sperm-binding proteins in the ventral prostate of the golden hamster].

Objective: To investigate the binding of secretory proteins in the ventral prostate to the surface of sperm.

Methods: We used different techniques to demonstrate the possibility of ventral prostate secretory proteins binding to sperm in golden hamsters. Polyclonal antibodies against crude secretion of the ventral prostate cultured in rabbits were used to detect the antigens in hamster epididymal, uterine and oviductal spermatozoa by indirect immunofluorescence technique. The uterine and oviductal spermatozoa were collected after mating with the males with or without ventral prostate glands. The ventral prostate secretory proteins were isolated and transblotted to the membrane, which was incubated with the biotinylated epididymal sperm membrane proteins, and then the biotinylated binding proteins were stained.

Results: An immunoreaction restricted to the middle piece was observed in the sperm incubated with the ventral prostate secretion and ejaculated sperm recovered from the uteri and oviducts. The rate of the epididymal sperm bound with the ventral prostate secretory proteins was (80 +/- 5) %, and the rats of the sperm binding to the ventral prostate secretory proteins were (30.0 +/- 4.6) % from the uterus and (16.0 +/- 3.6) % from the oviduct after mating with the males with ventral prostate glands, significantly higher than after mating with those without prostate glands (P < 0.01). Five bands were identified by Western blot analysis in vitro of the ventral prostate secretory proteins incubated with biotinylated epididymal sperm membrane proteins.

Conclusion: The present data indicate that ventral prostate secretory proteins bind to the middle piece of sperm in golden hamsters.