Failure of TSH Antisera To Neutralize Long-Acting Thyroid Stimulator

Abstract

Rabbits were immunized against bovine pituitary TSH (Thytropar) and against human pituitary TSH. The antiserum to bovine TSH, at concentrations as low as 1 in 25, completely neutralized 1.0 mU/ml of U.S.P. Thyrotropin Reference Substance (bovine). Partial neutralization occurred with an antiserum concentration of 1 in 125. Similar concentrations of the antiserum to human pituitary TSH were effective against the TSH present in serum from a myxedematous patient. The bovine TSH antiserum had only weak action against the TSH in myxedema serum, partial neutralization occurring at an antiserum concentration of 1 in 2. Similarly, the human TSH antiserum was only weakly active against bovine TSH, partial neutralization occurring with an antiserum concentration of 1 in 5. Neither antiserum had any demonstrable action against long-acting thyroid stimulator present in serum from a thyrotoxic patient.