Radioiodine metabolism in the chick embryo.

Abstract

Many studies have been made of the histology of the thyroid gland at various stages in the development of the chick embryo. These studies, as well as several to detsrmine the age of the chick embryo at which biochemical differentiation or thyroid function begins, have recently been summarized by Moore (1950). Methods used to determine thyroid function in the chick embryo include measurement of the total iodine in the thyroid glands (Sun, 1932), demonstration of the presence of the thyroxine in the chick thyroid by tadpole test (Hopkins, 1935), and demonstration of organic binding of radioiodine in the thyroid gland by autoradiography (Hansborough and Khan, 1951). Using these methods, it was not possible to detect any evidences of thyroid function or biochemical differention prior to the tenth day of incubation, which is the time colloid has been reported to appear in the thyroid gland (Bradway, 1929; Hopkins, 1935; Venzke, 1949).