Seminal fibronectin-like antigen and transferrin concentrations in infertile and fertile men.

Fibronectin like antigen (Fn) and transferrin (Trs) levels were measured in the seminal plasma of 40 fertile and 102 infertile men. The concentrations of both proteins were significantly (P < 0.001) higher in the fertile controls compared to the infertile groups. The levels of Fn and Trs (mean value +/- SEM) in the fertile men were 857.9 +/- 9.8 micrograms ml-1 and 164.0 +/- 6.5 micrograms ml-1, respectively; in the azoospermic men (n = 17) 552.7 +/- 24.65 micrograms ml-1 and 20.7 +/- 2.19 micrograms ml-1, respectively; in the group of severe oligozoospermia (n = 35) 568.34 +/- 25.7 micrograms ml-1 and 31.1 +/- 4.18 micrograms ml-1, respectively; in the moderate oligozoospermic group (n = 8) 572.50 +/- 47.9 micrograms ml-1 and 43.4 +/- 15.4 micrograms ml-1 respectively, and in the asthenozoospermic group (n = 26) 512.76 +/- 40.4 micrograms ml-1 and 47.0 +/- 7.9 micrograms ml-1, respectively. Of special interest was the finding from a group of 16 normospermic men (partners of couples with unexplained infertility) who showed significantly lower levels of Fn like antigen, 632.5 +/- 26.9 micrograms ml-1 (P < 0.001) and Trs 41.8 +/- 6.94 micrograms ml-1 (P < 0.0001) compared to normals. No correlation was found between Fn levels with either Trs or FSH levels or sperm count. In conclusion, our results indicate that male infertility is associated with changes in seminal plasma Fn like antigen concentrations and that it can be possibly used as an index of sperm fertilizing capacity.