The level of adrenomedullin immunoreactivity in seminal fluid is higher in oligozoospermic subjects and correlates with semen biochemical parameters

Objective

The newly discovered vasoactive peptide, adrenomedullin, and its receptors are widely distributed in various non-vascular tissues. Recent studies have suggested the possible regulatory role of adrenomedullin (AM) at several levels of the pituitary-gonadal axis. We determined the level of adrenomedullin-like immunoreactivity in the seminal fluid and examined its possible correlation with routine semen parameters, semen biochemical levels or plasma levels of FSH, LH, testosterone or prolactin.

Materials and methods

A total of 51 males were divided into three groups according to semen analysis: (i) normospermic (n = 19); (ii) oligozoospermic (n = 17); (iii) azoospermic (n = 15). All the subjects were submitted to hormone analysis (LH, FSH, testosterone, prolactin), routine semen parameters and semen biochemical levels (fructosio, citric acid, l-carnitine, nitric oxide) evaluation. AM was determined in plasma and seminal fluid using a specific radioimmunoassay.

Results

Mean AM concentration in seminal plasma was higher in oligozoospermic subjects than in normospermic males. In patients with non-obstructive azoospermia AM in semen was significantly lower than in patients with obstructive azoospermia. Semen AM levels correlated negatively with citric acid concentrations in oligozoospermic subjects. In patients with obstructive azoospermia AM in seminal fluid was correlated with citric acid levels. There was a relationship between plasma AM and prolactin.

Conclusions

We conclude that in human seminal fluid AM concentration is increased in infertile oligozoospermic patients and derives very likely from the prostate. Its role in the regulation of male fertility, however has to be understood.