Perchlorate induces hermaphroditism in threespine sticklebacks.
Recently, concern regarding perchlorate contamination has arisen in many contexts. Perchlorate has many military, commercial, and domestic applications, and it has been found in milk, drinking and irrigation water, and produce. Perchlorate is harmful at low levels, yet it remains unregulated in the United States while the U.S. Environmental Protection Agency attempts to establish acceptable exposure levels. The present study investigated potential reproductive effects on vertebrates using a model fish species, the threespine stickleback (Gasterosteus aculeatus). Sticklebacks were raised from syngamy through sexual maturity in untreated water and in three target concentrations of sodium perchlorate-treated water. Perchlorate was found to interfere with the expression of nuptial coloration, courtship behavior, and normal sexual development. Genetic testing revealed that some females were masculinized to the extent that they produced both sperm and eggs, and histological analysis showed that these individuals had intersexual gonads (ovotestes) containing both oocytes and cells undergoing spermatogenesis. In vitro fertilizations revealed that those gametes were capable of self- and cross-fertilization. However, crosses using sperm derived from genetic females died either during the blastula phase or near the onset of organogenesis. Sperm derived from genetic males produced viable fry when crossed with eggs derived from genetic females from all treatments. To our knowledge, the present study provides the first evidence that perchlorate produces androgenic effects and is capable of inducing functional hermaphroditism in a nonhermaphroditic vertebrate.
Bernhardt
Richard R
RR
Department of Biological Sciences, University of Alaska Anchorage, 3211 Providence Drive, Anchorage, Alaska 99508-4614, USA. bernhard@alaska.net
von Hippel
Frank A
FA
Cresko
William A
WA
D000818:Animals; D001483:Base Sequence; D017931:DNA Primers; D005260:Female; D057850:Hermaphroditic Organisms; D008297:Male; D010472:Perchlorates / Q000633:toxicity*; D012098:Reproduction / Q000187:drug effects; D019849:Sex Determination Processes / Q000139:chemically induced*; D023701:Smegmamorpha; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D017931:DNA Primers; D010472:Perchlorates; D014874:Water Pollutants, Chemical; C494474:perchlorate