THE UPTAKE OF P32AS A MEASURE OF CELLULAR METABOLISM IN THE HUMAN THYROID*†

Abstract

Cellular metabolism in the thyroid gland of patients with Graves' disease, nodular goiter and thyroid cancer was appraised by measuring the incorporation of radiophosphorus (P³²). The P³² was administered intravenously twenty-four hours before operation. At the time of surgery, representative specimens were procured from thyroid, muscle and blood. The ratio of counts per minute per milligram of thyroid to counts per minute per .001 milliliter of serum was thought to be the most reliable index of P³² content. Representative “thyroidserum ratios” were as follows: normal thyroid, 23; Graves' disease treated with propylthiouracil and Lugol's solution, 33; Graves' disease treated with propylthiouracil alone, 49; follicular adenoma (nodular goiter), 20; fetal adenoma, (nodular goiter), 40; and carcinoma of the thyroid, 71. Administration of propylthiouracil and Lugol's solution to patients with hyperthyroidism seemed to have little demonstrable effect upon the total incorporation of P³². Neither was P³² uptake decreased in patients with suppressed hormone synthesis due to inhibition of TSH by l-triiodothyronine or desiccated thyroid. The data suggested that the amount of labeled phosphorus incorporated into the human thyroid at twenty-four hours is related more directly to cell density than to functional activity of the gland as judged by histologic criteria.