Determination of selenium in human spermatozoa and prostasomes using base digestion and electrothermal atomic absorption spectrophotometry.

A method for the determination of selenium in human spermatozoa and prostasomes is described. The samples were digested with 25% (w/v) tetramethylammonium hydroxide (TMAH) in methanol and analyzed by atomic absorption spectrometry with electrothermal atomization and Zeeman background correction (ET-AAS). Nickel was used as a matrix modifier. Calibration was performed using the matrix-based calibration curve. The TMAH-digestion method agreed well with a conventional digestion procedure using concentrated nitric acid. The TMAH-digestion does not require heating or strong acids and it was suitable for small biological samples. The average recovery of added selenium in spermatozoan digests was 95.1 +/- 5.2% (n = 5). The coefficient of variation was 9.1% (n = 21). The accuracy of the method tested with the NBS standard 1577 (bovine liver, certified at 1.1 +/- 0.1 micrograms Se/g) resulted in a value of 0.98 +/- 0.10 micrograms Se/g (n = 16). The method was further tested in an interlaboratory comparison study.

Semen selenium content and sperm mitochondrial volume in human and some animal species.

Selenium (Se) and glutathione peroxidase (GSH-Px) were determined from the seminal plasma samples and spermatozoa of human and four different animal species. The human sperm Se concentration was 1.8 +/- 0.8 micrograms/g dry weight, which was about half of that in the bull. Abnormal sperm morphology and motility correlated with low sperm Se content. The volume of sperm mitochondrial sheath in human, bull and stallion was measured using transmission electron microscopy. In these species the sperm Se content was highly correlated with the volume of mitochondria. Among the five species studied, the seminal plasma level of Se was lowest in human male and stallion, while the highest levels were encountered in the bull. No correlation was obtained between human semen quality and seminal plasma Se concentration. The seminal plasma GSH-Px activity was low in man and ram, absent in boar and stallion but very high in the bull. The amount of structural sperm Se as well as seminal plasma Se and GSH-Px activity appears to be highly variable in different species.

Lead, magnesium, selenium and zinc in human seminal fluid: comparison with semen parameters and fertility.

The concentrations of lead, magnesium, selenium and zinc in seminal fluid from men with variable semen quality (sperm morphology, density and motility) and fertility were determined by atomic absorption spectrometer without or with Zeeman background correction. The mean (+/- SD) concentration of selenium in the samples (n = 142) was 28.8 +/- 9.5 micrograms/l, which was about a third of the corresponding serum value (77.8 +/- 13.3 micrograms/l, n = 140). The serum selenium level was significantly (P less than 0.001) higher in infertile than in fertile men, but the seminal fluid did not show such a difference. No correlation was obtained between selenium values in seminal plasma and sperm density or motility. The levels of lead in seminal fluid were very low with no correlation to the levels of magnesium, selenium and zinc or the semen qualities. The seminal fluid lead concentration was significantly (P less than 0.001) higher in infertile (3.6 +/- 3.2 micrograms/l, n = 79) than in fertile men (1.7 +/- 1.0 micrograms/l, n = 39). Magnesium (103.5 +/- 49.2 mg/l, n = 90) and zinc (141.1 +/- 71.7 mg/l, n = 157) concentrations in seminal fluid were comparable with previous reports. Both minerals showed a positive correlation to the seminal fluid selenium, while only zinc displayed a borderline correlation with sperm density. The present findings indicate that the determination of seminal fluid selenium may not offer any advantages over zinc and magnesium measurement in the fertility assessment and its role in human semen remains obscure. The low lead concentrations in the present material is a clear indication of low industrial exposure.

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.