Seminal prolactin concentration and sperm reproductive capacity.

Prolactin (PRL) levels in the seminal plasma were determined in 63 men, all partners from infertile marriages. For comparison of seminal PRL concentration and semen quality, a sperm concentration and motility were studied in all men. Also, for determination of the fertilizing capacity of the semen, a zona-free hamster ovum penetration test was done in 49 men, while 14 men were studied by determination of the fertilization of human oocytes in vitro. Significantly higher levels of semen PRL were found in those individuals with low sperm concentration and motility as well as in those individuals that showed an abnormal hamster ovum penetration test. This suggests that high seminal PRL levels have a negative impact on sperm functional capacity.