Interactions of thyroid hormones with L-(3H) glutamate binding sites, with special reference to N-methyl-D-aspartate receptors.

An L-(3H)glutamate binding assay was developed in which 82% of the specific binding is to a site that corresponds to the N-methyl-D-aspartate receptor. The effects of various anticonvulsants and thyroid hormones were investigated with this assay. Anticonvulsants did not affect L-(3H)glutamate binding, while L- and D-isomers of triiodothyronine and thyroxine inhibited L-(3H)glutamate binding significantly. Scatchard analysis showed that thyroid hormones interacted with L-(3H)glutamate binding competitively. The interactions of thyroid hormones with NMDA-sensitive L-(3H)glutamate binding may be one of the mechanisms by which these hormones affect the central nervous system.