THYROTROPIC HORMONE IN INFANTS AND CHILDREN<subtitle>Differentiation Between Primary and Hypopituitary Hypothyroidism</subtitle>

THYROID FUNCTION STUDIES IN CHILDREN: NORMAL VALUES FOR THYROIDAL I131UPTAKE AND PBI131LEVELS UP TO THE AGE OF 18*

“…REPORTED ON NORMAL CHILDREN Listed in Table 5 are the pertinent radioiodine studies on normal children as reported from various areas of the United States (1)(2)(3)(4)(5)(6)(7)(8). Thyroidal I 131 uptake values at twenty-four and forty-eight hours reported from the East and West Coasts are much lower than our data.…”

“…The children were in a sitting position in front of a scintillation counter. 2 Readings lasting three minutes each were taken at two distances in order to minimize the errors due to geometry (50 and 70 cm. from the center of the counter to the estimated center of the thyroid gland) (11).…”

“…All but one of the previous studies concerning children have been limited, in that only the concentrating ability of the thyroid for iodine has been tested. This function was measured as the percentage thyroidal uptake of the administered dose at twenty-four hours (1)(2)(3)(4)(5)(6) or at forty-eight hours (7). In one study (8), the secretion rate of proteinbound radioiodine (PBI 131 ) of serum was measured at various intervals after I 131 administration, but there was no information about the age groups tested.…”

“…Obtained from Abbott Laboratories, through license from the U. S. Atomic Energy Commission 2. The scintillation probe and well-counter were obtained from Nancy "Wood Counter Laboratories.The Endocrine Society.…”

Rates of I131-Labeled Thyroxine Metabolism in Euthyroid Children

“…Although the plasma concentration of thyroid hormone in newborn infanits is appreciably higher than in adults, in children there appears to be no significant difference (4)(5)(6)(7)(8)(9). The present study of thyroxine metabolism was designed to further define thyroid hormone metabolism in children.…”