Serum Iodine Fractions in Subjects Receiving Potassium Iodide in Small Dosage*

Butanol-Extractable Iodine of Serum 1

“…In euthyroid pregnancy the SPI is elevated to 6.0 to 10.0 gamma per cent (17). The (8,9) are in agreement with our conclusion that the presence of inorganic iodine in serum would not in itself cause the elevation of SPI above the BEI of patients taking inorganic iodine.…”

“…The mean value for iodine extraced by butanol in the sera from 23 healthy males and nonpregnant females and 21 pregnant women amounted to 69 per cent of SPI (10). In five normal persons the ratio, butanolextractable iodine (BEI): SPI varied from 0.65 to 0.82 (8). BEI remained unchanged after the administration of potassium iodide, but both SPI and inorganic iodine increased (8,9).…”

“…In studies of medically treated hyperthyroid patients, however, a number of values for SPI proved unexpectedly high in comparison with other measures of thyroid activity (5,7). Danowski and associates (8)(9)(10) reported that SPI of normal individuals and pregnant women rose after the administration of potassium iodide. It had also been discovered that certain iodine-containing compounds commonly used for diagnostic and therapeutic purposes formed combinations with the proteins of the serum and therefore were measured with SPI (11).…”

“…In five normal persons the ratio, butanolextractable iodine (BEI): SPI varied from 0.65 to 0.82 (8). BEI remained unchanged after the administration of potassium iodide, but both SPI and inorganic iodine increased (8,9).…”

“…Taurog and Chaikoff (4) found that 73 to 93 per cent of the iodine of normal plasma behaved like thyroxine inasmuch as it remained in butanol extracts after these had been washed with Blau's reagent. Danowski and associates (8)(9)(10) compared the iodine extracted by butanol with SPI in the sera of normal individuals, pregnant women, and persons taking potassium iodide. The mean value for iodine extraced by butanol in the sera from 23 healthy males and nonpregnant females and 21 pregnant women amounted to 69 per cent of SPI (10).…”