THIS PAPER presents data on the effect of the thyrotropic hormone1 on I131 uptake by the thyroid for the differentiation of primary from secondary hypothyroidism in infancy and childhood.
While hypothyroidism in infancy and childhood has been the subject of much clinical research since the turn of the century, only minor amendments have been made to the excellent clinical classification presented by Pineles in 1902.2 Much has been learned, however, about the chemistry and physiology of pituitary and thyroid function, and from these certain practical laboratory aids in diagnosis have been standardized and are available to most clinicians for routine use. Among these, in hypothyroidism, are roentgenographic evidence of retardation of skeletal maturation, failure of linear bone growth, epiphyseal dysgenesis,3 chemical and metabolic evidence of lowered basal metabolic rate,4 low serum alkaline phosphatase,5 elevated serum cholesterol,4 and hypercarotinemia.6
During the past decade the