[Estrogenic activities of parabens].

Studies indicated that parabens, used as anti-microbial agents in food, cosmetics, and pharmaceuticals, produced a positive uterotrophic response in vivo. They also damaged the late stages of spermatogenesis, altered proportion of pups born alive, and body weight of offspring. They reduced the number of sperm in the epididymis, and the sperm motile activity in male offspring. Parabens could compete with [3H] 17beta-estradiol for binding to the estrogen receptor. The proliferation of two estrogen-dependent cell lines MCF-7 and ZR-75-1 could be increased by parabens. They also increased expression of both transfected and endogenous estrogen-regulated genes in MCF-7 cells. The studies demonstrated parabens were weakly estrogenic.