A STUDY OF THYROID STIMULATING ACTIVITY IN HUMAN SERUM WITH THE HIGHLY SENSITIVE CYTOCHEMICAL BIOASSAY1

Abstract

The cytochemical bioassay is able to detect minute amounts of thyrotropin and thyroid stimulating immunoglobulins. Estimations of serum TSH by the cytochemical bioassay are in good agreement with values obtained by radioimmunoassay. In untreated hyperthyroid patients with Graves' disease the TSH levels are significantly lower than in control subjects. Thyroid stimulating immunoglobulins showed a delayed time course of action in the bioassay and this provided a convenient method of distinguishing between the two thyroid stimulators.