PROTEIN-BOUND IODINE LEVELS IN MOTHERS AND INFANTS AT BIRTH BY

The protein-bound iodine level in the blood is important in relation to thyroid gland activity. Various aspects of blood iodine are discussed by Samson Wright (1952). Iodine is present in the blood in the hormnone form of thyroxine and diiodotyrosine bound with albumin and pre-cipitated out with the serum proteins, the protein-bound or precipitable iodine; the normal range of this hormone iodine is 3-5 to 8 ~tg. per 100 ml. Kennedy and Hayles (1 948) mention that protein-bound iodine levels may be raised to values of 10 to 12 sag. per 100 ml. during pregnancy and-in early infancy. Iodine is also found in the blood as inorganic iodide or filterable iodine, the level of which is dependent on iodine intake; this is not related to thyroid gland activity as is the protein-bound iodine. In patients with hypothyroidism the protein-bound iodine levels are reduced; in hyperthyroidism the level is raised. The present report represents a study to deter-mine normal levels of protein-bound iodine in the serum of mothers taken within an hour of the delivery of an infant and the levels in the serum of umbilical cord blood of their infants taken immedi-ately after delivery. The protein-bound iodine was determined by the method of Connor, Swenson