Thyroid Cancer in Rats From Ethylene Thiourea Intake

Abstract

Administration of 350 and 175 parts per million ethylene thiourea in the diet of male and female Charles River CD rats led to a dose-related induction of follicular and papillary thyroid cancers, with pulmonary metastases, and of related lesions such as thyroid solid-cell adenomas and hyperplastic and simple goiter. The first tumor was found after 68 weeks; most cancers occurred after 18–24 months when the study was terminated. Control rats did not show these lesions.