Serum prolactin in professional soccer players.

Background: There is little information on the influence of regular physical exercise on baseline prolactin levels in male athletes, especially in professional soccer players. Therefore, the aim of this article was to compare serum prolactin levels in professional sports men with those of a control population of healthy, sedentary, male blood donors. Patients and methods: Serum prolactin was measured in 31 members of a professional soccer team playing in the Italian major league ("Serie A"), and in a control population of 195 healthy, sedentary, male blood donors. Athletes had rested 24 hrs since the previous training session. All samples were collected in the morning after an overnight fast and a minimum of 30 min rest before venipuncture. Results: No significant differences could be observed in the morning concentration of serum prolactin between athletes and sedentary controls (12.9 +/- 1.0 vs. 11.8 +/- 0.8 ng/mL; P = 0.471). The percentage of athletes displaying values outside the age- and sex-specific reference range did not differ significantly from that of the control population (<3.4 ng/mL: 0 vs. 1%, P = 0.642; >16.2 ng/mL: 29 vs. 23%, P = 0.154). Conclusions: Results of our investigation show that the baseline (morning) concentration of serum prolactin might not vary significantly in response to regular physical exercise. Therefore, the reference range for the general population of young male adults might also be used for professional soccer player sand, probably, other sportsmen with a similar physical workload.