The Etiology of Goiter in Chicks from Thyroprotein-Fed Hens; Negative Role of Inorganic Iodide

It has been shown that goiters could be produced in chicks by feeding inorganic iodide to the hen (Wheeler and Hoffmann 1949a). This was not unexpected because it had previously been shown that goiters could be produced in chicks by injecting KI into 16-day old embryonated eggs (Wheeler and Hoffmann, 1949b). These findings suggested that inorganic iodide present in synthetic thyroprotein (STP) might cause the goiters found in chicks from hens fed STP. The goiters produced by either inorganic iodide or STP were comparable in weight and histologically indistinguishable (Wheeler and Hoffmann, 1948) and it was known that STP contains 1.5–2.0 percent inorganic iodide (Graham 1948). Thus it appeared likely that inorganic iodide might be the goiterogenic substance in thyroprotein. To test this hypothesis, an iodide-free sample of synthetic thyroprotein was obtained from Dr. W. R. Graham, Jr. of Cerophyll Laboratories, Kansas City, Missouri. Four groups of ten hens were . . .