Epidemiological studies related to the use of hormonal agents in animal production.

The principal types of hormonal agents used in the production of meat for human consumption are estrogens, progestagens, and androgens. Only the last class is truly anabolic. Each type of compound named above has fairly characteristic toxic effects after prolonged intake. In this review, an attempt will be made to relate available information from experience with the administration of these three types of hormones to humans to the question whether sufficient amounts of these chemicals can remain in meat cut from carcasses of animals administered hormones during finishing to have deletarious effects on human ingesters. Present indications are that administration of stilbestrol to pregnant women may result in a somewhat increased incidence of cervical and vaginal cancers in their daughters; such administration appears to have no effect on the incidence of cancers in sons and only slight, if any, effect on that in the mothers. Other estrogens seem to have no specific effects on the incidence of cancer. Progestagens also are not known to induce any specific lesions. Although many androgens are known to produce edema, fever, and jaundice, they have not been found to cause specific lesions to any significant extent. With reference to stilbestrol, the doses given to the mothers of affected children have ranged between 5 and 125 mg/day. Because muscle, liver, and kidney from steers treated with stilbestrol in the usual way (s. c. implantation of a pellet at the base of an ear) have been found to contain less than 0.5 ppb of stilbestrol one month after implantation of the pellet, it is obvious that, to approach even the lowest clinically used dose of stilbestrol, a person would have to eat daily a quantity of such animal products that would be impossible to ingest. The findings that a mean of 26.4% of an oral dose of stilbestrol is excreted within 24 hours and that 99.5% is excreted within a week indicate that cumulation of this chemical within the body from the low level of intake provided by meats is not likely to reach a significant level. This would be so even though the animal product contained more than the 0.5 ppb mentioned above.