Seminal transforming growth factor-β in normal and infertile men

Transforming growth factor-beta (TGF beta) is a cytokine with autocrine and paracrine action in the testis and potent immunoregulatory and anti-inflammatory activities, In the present study, we examined the concentration of latent (acid-activatable) and free (active) TGF beta in seminal plasma from normal subjects (n = 23) and infertile (n = 40) patients, by using a TGF beta specific immunoenzymological assay, and a bioassay (CCL64 cell line growth inhibition) detecting any form of TGF beta, Free TGF beta 1 was present in normal subjects at a concentration (1.82 +/- 1.06 ng/ml) close to that known to give maximal stimulation in vitro. In pathological groups, the mean concentrations were not significantly different from the normal ones. Latent TGF beta 1 was present in normal seminal plasma at a high concentration (92.4 +/- 29.2 ng/ml), In subjects with pathologies of both testis and genital apparatus, or with epididymal occlusion, mean latent TGF beta 1 concentrations were normal, whereas transferrin concentrations were lower. The concentrations found in the epididymal occlusion group indicate that TGF beta 1 is, for a large part, secreted by the genital tract. In the testicular pathology group, TGF beta 1 concentrations were 130.7 +/- 61.2 ng/ml, a mean not statistically different from normal, although higher, No differences were found between patients with high and normal blood plasma follicle stimulating hormone, and this is consistent with the notion that most TGF beta 1 in seminal plasma is not of testicular origin. The TGF beta bioassay ensured that immunologically detected TGF beta was present in a bioactive or bioactivatable form, Furthermore, the values found in normal and pathological seminal plasmas were usually higher than those detected by the immunoassay, suggesting that other forms of TGF beta might be present, Together, the present data show that very large amounts of TGF beta are present in human seminal plasma. The TGF beta ligand assay in the seminal plasma appears to indicate no differences between normal and infertile subjects.