THE POSSIBLE MEANING OF TRANSFERRIN AND ITS SOLUBLE RECEPTORS IN SEMINAL PLASMA AS MARKERS OF THE SEMINIFEROUS EPITHELIUM

Transferrin (Tf) and soluble transferrin receptors (S-Tf-R) were measu red by enzyme immunoassay in seminal plasma of 130 semen samples. The mean concentration of S-Tf-R in cases with normozoospermia was 10.4 IU /ml (95% confidence interval: 9.5-11.3) and it was significantly lower in patients with oligozoospermia (6.6, 95% CI: 5.8-7.5, P < 0.001), a sthenozoospermia (8.5, 95% CI: 5.5-10.7, P < 0.05), azoospermia of pri mary testicular origin (7.9, 95% CI: 6.1-9.6, P < 0.05) and post-vasec tomy samples (5.9, 95% CI: 5.4-6.9, P < 0.001). The concentration of S -Tf-R in post-vasectomy samples was lower than that in patients with a zoospermia of primary testicular origin (P < 0.05; positive likelihood ratio = 7 at value of 8.3 IU/ml). S-TfR was positively correlated wit h motile sperm concentration (r = 0.50, P < 0.0001), percentage motili ty (r = 0.38, P < 0.001), percentage of normal forms (r = 0.43, P < 0. 001), sperm linear velocity (r = 0.42, P < 0.001), and ATP concentrati on (r = 0.67, P < 0.0001). Follicle stimulating hormone (FSH) was foun d to be negatively correlated with the concentrations of both Tf (r = -0.31, P < 0.05) and of S-Tf-R (r = -0.45, P < 0.01). The mean concent ration of Tf in seminal plasma was 50.4 mu g/ml (35.9-67.2) in samples with normozoospermia (n = 22), and the concentration was significantl y lower in patients with oligozoospermia (P < 0.05), azoospermia of te sticular origin (P < 0.001), and post-vasectomy samples (P < 0.001). S eminal Tf was correlated with motile sperm concentration (r = 0.36, P < 0.001), percentage of motile spermatozoa (r = 0.25, P < 0.05), linea r velocity (r = 0.24, P < 0.05) and ATP concentration (r = 0.44, P < 0 .001). The concentration of Tf was positively correlated with that of S-Tf-R both in cases with spermatozoa present (r = 0.66, P < 0.001), a nd in cases with azoospermia of testicular origin (r = 0.51, P < 0.05) but not in vasectomy cases. It is concluded that S-Tf-R in seminal pl asma is a marker of spermatogenesis and may give information on the pr esence or absence of spermatogenetic cells in cases with azoospermia. Further investigations are needed to assess its usefulness for clinica l practice.