Concentration of calcitonin in seminal plasma of infertile men

Calcitonin levels in peripheral plasma (8 cases) and seminal fluid (30 cases) were measured by direct Radioimmunoassay (RIA). Their relationship with seminal characteristics, calcium and swelling test were evaluated. Seminal plasma calcitonin averaged 7530 pg/ml which amounts to 142 times higher than that of serum averaging 53 pg/ml. There was no significant difference in the mean seminal plasma concentration of immunoreactive calcitonin (iCT) among normozoospermic, oligozoospermic and azoo-spermic groups. However, there was a significant difference (p less than 0.05) in the seminal plasma mean concentration between high and low motility groups. A significant correlation was found between iCT seminal plasma concentration and percent of motility (p less than 0.05), yet, no correlation was detected between iCT and other seminal characteristics including swelling test (p greater than 0.05). Seminal plasma calcium averaged 175.3 +/- 29.9 mg/L which was 1.75 times higher than that of the serum averaging 100.32 +/- 5 mg/L. No significant difference (p less than 0.05) was obtained between high and low motility groups as regard their calcium seminal plasma levels. A significant correlation was found between seminal plasma concentration of calcium and calcitonin (p less than 0.05), but not with the percent of motility (p less than 0.05). Calcitonin (CT) was present in seminal plasma in higher concentrations than those of serum, indicating its active secretion within the male accessory sex glands. The role of CT in human reproduction needs further elucidation, especially regarding sperm motility.