IT WAS discovered in the 1940s that synthetic and natural estrogenic hormones increased fat production in chickens. As a result, pellets of diethylstilbestrol (DES) were implanted in young chickens to improve the quality of their carcasses. This practice was discontinued some years ago. The effect of DES, fed or implanted, on beef cattle differs from the effect on chickens; it leads to a more rapid production of lean meat and improves the efficiency of conversion of feed into beef. Diethylstilbestrol is metabolized by conversion into the glucuronide in the liver of cattle and is excreted in the urine. The residues in beef carcasses following DES treatment were very low, but they were detected in the livers of some animals.
Diethylstilbestrol resembles all estrogens that have been tested in producing mammary tumors in susceptible strains of mice. Therefore, DES is a carcinogen. For many years, estrogens for clinical use have carried
Jukes TH. Estrogens in Beefsteaks. JAMA. 1974;229(14):1920–1921. doi:10.1001/jama.1974.03230520062040
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