Evaluation of ascorbate and urate antioxidant capacity in human semen

Abstract

The ascorbate/urate ratio in the seminal plasma was studied in 76 randomly chosen infertile men. The levels of ascorbate and urate were found to vary widely (range: 93-954 pmol 1-' and 127-670 pmol 1-', respectively), while the ascorbate/urate ratio was 1.03 f 0.63 (mean & SD), indicating almost equimolar concentrations of both compounds in more than 60% of the subjects investigated. No relationship of ascorbate with any biochemical marker of accessory sex gland secretions was observed, whereas an inverse correlation of urate with some prostatic markers, acid phosphatase (-0.37; P<O.OOl), zinc (-0.35; P<0.002) and citric acid (-0.33; P< 0.003), was found. In vitro experiments were conducted on an artificial suspension containing ascorbate and urate at physiological levels and activated polymorphonuclear leukocytes in the normal range (as proposed by WHO) to determine the extent to which the presence of superoxide anion-generating leukocytes contribute to the depletion of ascorbate and urate. The ascorbate level did not change in the presence of 0.2 x lo6 leukocytes ml -', while higher amounts of activated polymorphonuclear leukocytes initiated ascorbate oxidation, the intensity of which was in correlation with the extent of leukocyte contamination. After incubation (37 "C, 30 min) in the presence of 0.4, 1.0 and 1.5 x lo6 cells ml-', the average decline from the initial ascorbic acid level was 24, 43 and 49%, respectively. However, exposure of whole semen, instead of buffer, to oxidants released from the same amount of activated polymorphonuclears led to only 2.6, 11 and 22% decrease of the ascorbic acid, most probably due to the action of other superoxide anion scavenger compounds present in semen. Excessive superoxide anion production due to the presence of activated leukocytes had no influence on urate level either in the artificial suspension or in semen. The ability of ascorbate to afford protection against leukocyteassociated superoxide anions is not hampered in the semen of infertile men, provided that leukocyte contamination does not exceed 1 x lo6 cells ml-'. The possible role of urate in stabilizing the ascorbate antioxidant activity in seminal plasma should be further investigated.

Influence of Seminal Plasma Antioxidants and Osteopontin on Fertility of the Arabian Horse

“…Nevertheless, normozoospermic patients showed lower ascorbic acid concentrations than control men [5]. A relative decrease in ascorbate in semen is not a major cause of infertility in men [28]. Equine seminal plasma contains high CAT activity and this activity is lower in normal ejaculates than abnormal ejaculates [33].…”

“…Uric acid is a normal constituent of seminal plasma not only in humans where their occurrence is not limited to semen but in other mammals, including bull, ram, and boar, in which the metabolism of purines in the body does not normally terminate in uric acid [26]. It has been recognized that in addition to the cryoprotective effect of urea on living cells [27], urates and thiols represent the major chain-breaking antioxidants in mammalian seminal plasma [28,29]. Although no difference was observed between the age groups B and C, it appears that there is a trend toward reduced GPx activity after middle age.…”

Withania somnifera Improves Semen Quality in Stress‐Related Male Fertility

“…Seminal plasma lipid peroxides (LPOs) were estimated according to the method of Ohkawa et al [19], superoxide dismutase (SOD) and catalase activities according to McCord and Fridovich [20] and Aebi [21], respectively, and GSH and vitamin C according to Hissin and Hilf [22] and Gavella et al [23], respectively. Vitamins A and E were measured by high-performance liquid chromatography (HPLC) as per the modified method of Omu et al [24].…”

Mucuna pruriens Reduces Stress and Improves the Quality of Semen in Infertile Men

“…An appropriate standard solution of ascorbic acid (0.1 ml) was also run simultaneously. Brown color was developed and measured by spectrophotometer at 578 nm (24). …”