PARALLEL ASSAYS OF THYROTROPHIN, LONG-ACTING THYROID STIMULATOR AND EXOPHTHALMOS-PRODUCING SUBSTANCE IN ENDOCRINE EXOPHTHALMOS AND PRETIBIAL MYXEDEMA.

Abstract

TSH, LATS and EPS have been assayed in plasma and tissue samples from euthyroid and hyperthyroid subjects with and without exophthalmos (defined as ocular protrusion greater than 20 mm on ophthalmometry). In all cases of exophthalmos plasma LATS was elevated; TSH and EPS were not consistently found in this condition. In the plasma of some nonexophthalmic patients LATS was also found. In a euthyroid exophthalmic patient who died of intercurrent pneumonia, LATS was found in plasma, but not in pituitary or thyroid homogenates, whereas EPS was present in the pituitary homogenate, but not in plasma. In 3 patients with pretibial myxedema, high LATS values were found in plasma and in homogenates of biopsy material from involved areas. Massive doses of adrenal corticosteroid appeared to improve the exophthalmos in one patient, at the same time lowering plasma LATS activity. A smaller dose was ineffective in another patient.