Thyroxine excretion, a possible cause of goiter.

Abstract

TWENTY-FIVE years ago McCarrison (1) described an iodide resistant goiter in rats kept under “unsanitary” conditions or fed soy bean meal. A more thorough report was later presented by Sharpless, et al. (2) who showed that rats fed soy meal required two times more dietary iodide to prevent goiter than control rats. It was suggested but not demonstrated that these goiters may have been due to a thiocyanate-type substance in the soy meal. Wilgus, et al. (3) and Halverson, et al. (4) have amply confirmed the goitrogenic action of soy flour. Astwood (5) observed that the goiter in soy-fed rats exhibited a very high 6-hour uptake of I131. This latter observation reduced the likelihood of thiocyanate or propylthiouracil type goiters which, typically prevent retained uptake of I131. At present, all known goitrogenic substances (except thyrotrophic hormone) interfere with thyroid function and cause decreased uptake of I131. Soy bean flour, therefore, must be different since it produced