Stilbenes

The bad reputation of hormones is mainly caused by the harmfulness of diethylstilbestrol (DES). The properties of DES as a growth promoter were discovered in 1954 in the USA. It has been widely used as a feed additive or as an implant into the ear to promote growth and increase feed efficiency in cattle and sheep (until 1979 in the USA). DES is a non-steroidal estrogenic agent which does not occur naturally. The estrogenic effect is mainly ascribed to the same spatial distance of the two OH-groups as for estradiol. Hexestrol and dienestrol are synthetic non-steroidal estrogens that are structurally related to DES. Based on their carcinogenity, the EC banned their use in food producing and no residues of these anabolics should be present in animal products imported or produced within the EC (Directive 96/22/EC).

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