EXOPHTHALMOS-PRODUCING SUBSTANCE IN HUMAN SERUM*

Abstract

Small carp were used for the determination of exophthalmos-producing substance (EPS) in serum. They are easy to maintain and show no seasonal variations in response to EPS. Readily reproducible results were obtained. The regression lines for a pituitary extract and for pooled serum of exophthalmic patients showed the same slope. Sera of 9 normal persons caused no increase of the intercorneal distance in the fish. The sera of 38 patients with various thyroid disturbances were assayed. In exophthalmic patients, who at the time of the determination were thyrotoxic, EPS values tended to be higher than in those who were euthyroid. Among 7 patients with thyrotoxicosis but without proptosis, only 2 had serum which elicited a positive response. EPS values were high when the exophthalmos showed "malignant" features. In the sera of 4 patients with unilateral proptosis, high EPS activity was found. Of 2 patients with pretibial myxedema, one had "malignant" exophthalmos and a high EPS titer, whereas the other had no proptosis and a low EPS titer.