On incubation of long acting thyroid stimulator with human thyroid and adrenal homogenates.

In view of the ability of long acting thyroid stimulator (LATS) containing sera and IgG samples to stimulate the adrenal cortex of the mouse, it was decided to study the effect of incubation of LATS containing IgG with human thyroid and adrenal homogenates. Whereas incubation with human thyroid gland abolished (loss greater than 80%) both the thyroid and adrenocortical stimulatory effects of LATS, incubation with human adrenal gland resulted in a minimal loss (20%) of both of these stimulatory activities; the magnitude of this loss was no greater than that attributable to non-specific absorption observed with liver and kidney homogenates by previous workers. It is suggested that a, human and mouse thyroid receptors for TSH/LATS are similar and that adrenocortical receptor for ACTH/LATS are different; and b, the inability of human adrenal homogenates to neutralize LATS explains the absence of hyperadrenocorticism in patients with Graves' disease.