An immunoassay method for the determination of rat retinol-binding protein in serum and urine

Significance of simultaneous determination of serum and seminal plasma alpha-tocopherol and retinol in infertile men by high-performance liquid chromatography

High-performance liquid chromatography was used for the simultaneous determination of alpha-tocopherol and retinol in serum and semen of 40 subfertile men. The serum levels of the two vitamins were significantly higher in serum than in semen (3- to 10-fold) (P < 0.001). The mean alpha-tocopherol levels were higher in the serum and semen of men with normal sperm parameters (20 +/- 5 and 5 +/- 4 mumol L-1) than those with oligozoospermia (10 +/- 4 and 3 +/- 2 mumol L-1), azoospermia (8 +/- 3 and 3 +/- 1 mumol L-1) and asthenozoospermia (9 +/- 6 and 3 +/- 2 mumol L-1) (P < 0.002). Mean retinol levels in serum were similar in men with normal sperm parameters (2.4 +/- 2 mumol L-1) as in those with defective sperm parameters such as oligozoospermia (2.5 +/- 2 mumol L-) and asthenozoospermia (2.1 +/- 1.0 mumol L-) (P = 0.15), but significantly lower in men with azoospermia (1.3 +/- 0.3 mumol L-1) (P < 0.05). The alpha-tocopherol:retinol ratio was significantly higher in semen than in serum of men with normal sperm parameters (11.5) and those with asthenozoospermia (10.3) compared with ratios in those with oligozoospermia (8.3) and azoospermia (6.3). This may be related to reduced antioxidant activity in sperm dysfunction as a result of lipid peroxidation, from increased generation of reactive oxygen species.