Effect of 8-anilino-1-naphthalene sulfonic acid (ANS) on the interaction between thyroid hormone and anti-thyroid hormone antibodies.

Effect of 8-anilino-1-naphthalene sulfonic acid (ANS) on the interaction between thyroid hormone and anti-thyroid hormone antibodies was examined. Addition of 5.1 x 10(6) or 6.3 x 10(6) molar excess of ANS, respectively, enhanced the binding of 125I-T3 or 125I-T4 to their respective autoantibodies. However, further increase in ANS concentration resulted in a decrease in binding. These results suggest that the optimum concentration of ANS for the detection of anti-thyroid hormone antibodies is 5 approximately 6 x 10(6) molar excess of ANS to 125I-T3 or 125I-T4. On the other hand, addition of 10(4) molar excess of ANS concentration decreased the binding of 125I-insulin to anti-insulin antibodies. It was therefore suggested that the effect of ANS could be a nonspecific one and likely due to its negative charge.