Environmental and occupational exposure of metals and their role in male reproductive functions.

This review summarizes the effects of more than 20 metals that, research has indicated, may influence male reproductive health. Though males lack an apparent, easily measurable reproductive cycle, progress has been made in evaluating tests to identify chemical hazards and estimate reproductive health risks. Some agents discussed in this review are well known to have potential toxic effects on the male reproductive system, whereas some are not so well established in toxicology. This review attempts to cover most of the known toxicants and their effects on male fertility. The literature suggests a need for further research in those chemicals that are reactive and capable of covalent interactions in biological systems, as well as those defined as mutagens and/or carcinogens, to cause aneuploidy or other chromosomal aberrations, affect sperm motility in vitro, share hormonal activity or affect hormone action, and those that act directly or indirectly to affect the hypothalamo-pituitary-gonadal axis.