Effects of Thiouracil, Thyroprotein, and Estrogen upon the Basal Metabolism and Thyroid Size of Growing Chickens

ONE of the most recent and interesting fields of research in animal production is the study of the effects of drugs and hormones which influence growth and metabolism. Both in large animals and in poultry, there is intense interest in the fundamental and practical aspects of the use of synthetic estrogens, antithyroid drugs, and thyroactive iodinated casein. The research to be reported here was undertaken because there was little information in the literature concerning the effects of these drugs upon the basal energy metabolism of chickens. In this work, these three classes of drugs were represented, respectively, by dienestrol diacetate, thiouracil, and Protamone (an iodinated casein product having thyroxine activity). Thiouracil is highly goitrogenic when fed to growing chickens at a level of 0.1 or 0.2 percent of the diet, as shown by Astwood, Bissell and Hughes (1944); Mixner, Reineke and Turner (1944); Andrews and Schnetzler (1946); and others. It …