Sex-Associated Differences in Protein l Values in Urine: Immunochemical Detection of Protein l in Genital Tissues

Summary: Immunochemical methods were used to analyse sex-associated differences in urinary protein l concen-tration. Spot urine from seven normal men and seven women of reproductive age was collected in four sequentially divided fractions, and protein l concentration in each fraction was measured by an enzyme immunoassay using the Sandwich method: protein l values in the first of the sequential urine samples from the male subjects were remark-ably high (81.4 ± 80.4 μg/l; meari ± l SD), but were much lower in the remaining three fractions. In females, on the other hand, protein l values were low (0.7 ± 0.4 μg/l), were uniform in all four sequential fractions, and were close to those of the last three fractions of urine from male subjects. Based on this finding, protein l concentration was measured in 14 specimens of seminal plasma, where concentration of protein l was high (1259.1 ± 1716.5 μg/l; r nge, 201.9 to 6580.0 μg/l). On Western blotting, protein l in seminal plasma had a molecular mass of Mr 14000, the same s that of protein l purified from the urine of patients with chronic renal failure of probable plasma origin, and of concentrated male urine collected at the initiation of voiding, which is thus thought to come mainly from genital tissue. Protein l was found to be in high concentration (434.8 ± 504.6 μg/l) in five aspirated fluids collected at the ejaculatory duct after squeezing the prostate. Three prostate tissue extracts contained protein l concentrations ranging from 8.6 to 50.1 μg/l. Protein l is also present in seminal vesicle fluids (7.1 ± 2.8 μg/l; r nge, 2.3 to 9.