Cadmium’s disguise does damage to estrogen-sensitive tissues

With 15,000 tons produced each year for batteries, alloys, and pigments, the heavy metal cadmium is one of the most serious environmental pollutants. Chronic exposure can induce kidney damage and bone disease and is thought to cause cancer. A study in the August issue of Nature Medicine now shows that cadmium mimics the effects of estrogen, and suggests that even at relatively low doses cadmium might have wide-ranging effects on the body.

Mary Beth Martin and colleagues report that, in rats, cadmium induces several well-known estrogenic responses. These included increased uterine weight, changes in the endometrial lining and increased density of the epithelia of the mammary gland. Moreover, in utero exposure to cadmium affected mammary gland development and onset of puberty in female offspring. The results provide solid evidence that cadmium has estrogenic effects in the whole animal, and follow up on earlier studies reporting that cadmium and other heavy metals such as nickel interact with the estrogen receptor. The new data also broaden the toxic repertoire of cadmium, which is a known kidney toxin, and was recently shown (Jin et al., Nat. Genet. 34, 326–329; 2003) to impair DNA repair processes in yeast.

The investigators did not perform dose-response studies but they found that cadmium induced potent estrogenic responses in rats at doses (5–10 micrograms per kilogram total weight) comparable to the Provisional Tolerable Weekly Intake recommended by the World Health Organization (7 micrograms per kilogram per week). In addition to pinpointing another mechanism for some of cadmium’s effects, the new data could call into question current regulatory standards for cadmium exposure.

Author contact:

Mary Beth Martin
Georgetown University, Washington, DC, USA
Tel: +1 202 687 3768
E-mail: martinmb@georgetown.edu