Stimulation of the human thyroid by infusions of plasma containing LATS protector

Abstract

LATS protector was tested for ability to stimulate the human thyroid gland by infusing plasma containing LATS protector into human volunteers. Infusions of plasma from normal, euthyroid subjects served as controls. Before receiving the infusions the recipients had been given tracer doses of125I (100-300 μCi) and were taking triiodothyronine (80-100 μg daily). Levels of125I in blood and urine were followed by counting plasma samples and urine samples. Three strong LATS protector plasmas caused a significant increase in the blood125I level and had a variable effect on the urinary excretion. A weak LATS protector plasma had a negligible effect. Three infusions of plasma from normal people had no effect. The infused LATS protector plasmas showed no detectable LATS (mouse bioassay) in 10-fold immunoglobulin concentrates. It was calculated that the levels of LATS protector attained in the volunteer subjects were l/10th to l/18th of the levels in the thyrotoxic patients from whom the LATS protector plasmas were obtained. We conclude that LATS protector stimulates the human thyroid gland. © 1974 by The Endocrine Society.