The effect of copper on the distribution of elements in human spermatozoa

Examination of intact individual human spermatozoa by X-ray microanalysis revealed that there was a correlation between particular elements in differnt regions of the cell. There was a constancy in the ratios of sodium to potassium in the head and mid-piece and of calcium to phosphorus in the mid-piece in any one sample, though the ratios varied between samples. This may have reflected the external environment since immersion in culture medium or cervical mucus had little effect on motility, yet markedly altered the sodium: potassium ratio. Incubation with copper wire in semen or cervical mucus significantly reduced the subcellular levels of both sodium and potassium inspermatozoa but did not affect the ratio between these two elements. The metal also displaced zinc from the head region, possible replacing it by copper. This may account for the decreased motility of spermatozoa in contact with copper ions. The observed toxicity of copper for human sperm cells lends support to the theory that part ofthe mode of action of the copper IUD may be due to an alteration in sperm fertilizing potential. Although the level of copper released by IUDs containing 200 mm-2 ofcopper wire exerted a minor toxic effect on spermatozoa, the elemental changes observed here may have great significance in the development of more efficient copper-releasing IUDs or an intracervical device whose action would depend on its spermatotoxiceffect.