REDUCED SENSITIVITY OF THE THYROID TO THYROTROPHIC HORMONE AND LATS FOLLOWING TREATMENT WITH ANTIMICROSOMAL ANTIBODIES

Abstract

ABSTRACT Antibodies raised against the microsomal fraction of the thyroid epithelial cells have been shown to inhibit in vitro binding of LATS to the microsomal fraction and to diminish in vivo thyroid stimulating effects of both LATS and TSH. Antimicrosomal antibody is also likely to block in vivo binding of LATS to the thyroid, and to reduce its rate of elimination from the circulating blood. The results are consistent with the assumption that the receptor structures and site of action of LATS and TSH in the thyroid are identical. On the basis of these findings the possibility arises that high titres of antimicrosomal antibodies in the serum may interfere with the results of LATS bioassay in such patients. Moreover, it seems reasonable to assume that in Hashimoto's thyroiditis high levels of antimicrosomal antibodies reduce the TSH sensitivity of thyroid, leading to an enhanced secretion of TSH and promoting the development of hypothyroidism.