The secretion of two hormones with identical function by the thyroid gland has been questioned, What is the relationship between these two hormones? Why does the thyroid secrete two hormones when either one can provide for all the activity of the thyroid (Greer, 1972). Little work has been done on the relationship between the two hormones. There is some evidence showing that thyroxine (T4) is deiodinated to triiouothyronine (T3) at the tissue level in mammals. Chambers (1970) found that there was a negative interaction between T4 and T3 when pharmacologic doses were administered to the rat. The present study was done to determine if such interaction occurred at physiologic levels of the two hormones and to see if T3,T4 interaction was present in other species. The rat and chick were studied since the thyroid hormones are transported in the circulatory system of the two animals by different plasma proteins. It was thought that the difference in transport might give some information about interaction.
College and Department
Plant and Wildlife Sciences
BYU ScholarsArchive Citation
Cornish, Kurtis George, "Interaction between triiodothyronine (T₃) and thyroxine (T₄) in the chick and the rat" (1973). Theses and Dissertations. 7662.
Poultry; Rats; Triiodothyronine; Thyroxine