Hyperprolactinaemia and hyperserotoninaemia: their relationship to seminal quality

Seminal quality and levels of blood serotonin (5-HT) and serum prolactin (PRL) were determined in 60 men attending an infertility service. Subjects were grouped according to normal or abnormal accessory sex gland function. Subjects with normal accessory sex gland function were further subdivided into groups with asthenozoospermia, polyzoospermia, normozoospermia, oligozoospermia, or azoospermia. Blood 5-HT levels were significantly higher in oligozoospermics (115.9 +/- 23.7 ng ml-1, P less than 0.05), and asthenozoospermics (90.0 +/- 8.2 ng ml-1, P less than 0.05), than in normals (68.5 +/- 5.3 ng ml-1), whereas serum PRL levels were higher in azoospermics (44.2 +/- 4.7 ng ml-1) than in normozoospermics (15.9 +/- 1.6 ng ml-1, P less than 0.01). Subjects with abnormal accessory sex gland function were also subdivided according sperm count and sperm motility categories. None of these subgroups showed differences in serum PRL levels or blood 5-HT levels. Men with hyperserotoninaemia had higher serum PRL levels, low sperm count, and low motile sperm concentration. Moreover, higher 5-HT levels may be observed in men with normal PRL levels and also associated with normal PRL levels and with hyperprolactinaemia, and hyperprolactinaemia may be observed also associated with normal serotonin levels. Hyperserotoninaemia was related to both diminished sperm count and sperm motility, whereas hyperprolactinaemia was related to low sperm count. When hyperprolactinaemia and hyperserotoninaemia were both present, additive effects were observed.