Newin VitroTests to Detect the Thyroid Stimulator in Sera from Hyperthyroid Patients by Measuring Colloid Droplet Formation and Cyclic AMP in Human Thyroid Slices1

Abstract

In an attempt to detect a thyroidstimulating substance in the sera of hyperthyroid patients, human and guinea pig thyroid slices were incubated directly in the sera of untreated hyperthyroid patients. The intracellular colloid droplets were enumerated in 25 follicles of the incubated slices. Eighty-two % of LATS-negative sera obtained from untreated hyperthyroid patients did stimulate intracellular colloid droplet formation in normal human thyroid slices. More than 0.1 mU/ml of bovine TSH was required to produce the increase of colloid droplets similar to that produced by LATS-negative sera. A similar increase in colloid droplet formation was also produced by LATS-IgG in human thyroid slices of normal tissue and Graves' disease as well. The sera from normal subjects were without effect in this respect. Both the sera from untreated hyperthyroid patients and LATS-IgG also stimulated the accumulation of cyclic AMP in human thyroid slices in vitro. Although LATS-IgG stimulated colloid droplet formation in guinea pig thyroid in vitro and in mouse thyroid in vivo but the LATS-negative sera from hyperthyroid patients failed to do so, it is not known whether LATS-negative sera contain a new thyroid stimulator distinct from LATS or whether a low concentration of LATS fails to stimulate the thyroid of the mouse and guinea pig because of species specificity in the thyroidal response to LATS.