Selenium in reproductive organs, seminal fluid and serum of men and bulls.

The concentrations of selenium in the reproductive organs, seminal fluid and serum of human males and bulls were analysed using an atomic absorption spectrometer with Zeeman background correction. The mean (+/- SD) concentration of selenium in human seminal fluid (33.4 +/- 14.1 micrograms/l, n = 70) was less than half the level detected in serum (78.2 +/- 9.9 micrograms/l, n = 32). In bulls, the mean selenium concentration in seminal fluid (457.4 +/- 108.7 micrograms/l, n = 113) was about nine times higher than in human males, while the level in serum (49.1 +/- 5.1 micrograms/l, n = 94) was significantly (P less than 0.001) lower than in human serum. The selenium concentration (500 +/- 244 micrograms/l) in the bovine seminal vesicle secretions were comparable to those in the seminal fluid and this gland appears to be mainly responsible for the high selenium levels in the seminal fluid. The mean selenium concentration in reproductive tissues of both species was highest in the testes. The distribution of selenium in the bovine epididymis was biphasic. The testicular and epididymal selenium are associated mainly with macromolecules of the spermatogenic cells and spermatozoa. It was concluded that studies in farm and laboratory animals do not necessarily form a reliable basis for conclusions with regard to human male reproduction, since selenium may have a different role and importance in the reproduction of various species.