ABSTRACT
Laboratory animals can be used to help elucidate the action of prolactin (PRL) because the various experimental conditions can be controlled in animal models so that an unequivocal effect of this hormone may be expressed. In addition to the rat prostate, PRL has been shown to stimulate prostatic growth in rabbits, mice, squirrels, and dogs. Since the rat prostate has been studied most extensively, the discussion is primarily devoted to the effect of PRL on the rat prostate. Although PRL-testosterone synergism in the rat prostate has been demonstrated, PRL in the absence of circulating androgen has no stimulatory effect on the prostatic growth and synthetic activities. PRL has been implicated as a factor in the development and progression of human prostatic cancer. PRL directly affects the prostate through the following two modes: PRL-testosterone synergism, in which PRL potentiates the effect of testosterone action on the prostate and acting alone without participation of testosterone or in the absence of circulating testosterone.
