Secretion of prostatic binding protein by rat ventral prostate: influence of age and androgen.

Rat ventral prostate of adult male rats contain a large amount of prostatic binding protein (PBP). Immunological evidence indicates that this protein is a specific secretion product of this gland. The amount and concentration of PBP in ventral prostate show marked changes as a function of age. PBP is low but detectable (0.009 and 0.002 U/mg prostate) in 5- and 10-day-old rats and increases thereafter in a biphasic way to adult levels (0.619 U/mg prostate). After castration of PBP drops to 0.054 U/mg prostate after 10 days and 0.030 U/mg prostate after 21 days. The concentration of PBP returns to precastration levels after 2 weeks of androgen treatment. Estradiol and progesterone are ineffective in this respect. The antiandrogen, cyproterone acetate, counteracts the stimulatory effect of testosterone propionate.