Phosphorylated secretory proteins from rat epididymis and their androgenic control

Slices of the rat epididymis were incubated with [32P]orthophosphate. Analysis of the radioactive proteins in the medium by two-dimensional gel electrophoresis and autoradiography revealed 6-phosphorylated secretory proteins from the epididymis of adult rats: Mr = 62 000; 66 000; 76 000; 68 000; 19 000 and 20 000. Studies of the epididymides of immature and 7-day-castrated adult rats indicated that these phosphorylated secretory proteins were controlled by androgens.