Journal of Clinical Endocrinology & Metabolism, Vol 77, 1164-1169, Copyright © 1993 by Endocrine Society

ARTICLES

Receptor cross-talk can optimize assays for autoantibodies to the thyrotropin receptor: effect of phenylisopropyladenosine on adenosine 3',5'-monophosphate and inositol phosphate levels in rat FRTL-5 thyroid cells

A Hidaka, F Okajima, T Ban, S Kosugi, Y Kondo and LD Kohn
Section on Cell Regulation, Laboratory of Biochemistry and Metabolism, National Institute of Diabetes and Digestive and Kidney Disease, National Institutes of Health, Bethesda, Maryland 20892.

Immunoglobulins (IgG) from patients with Graves' disease increase inositol phosphate (IP) as well as cAMP production in rat thyroid FRTL- 5 cells; IgGs from normal control subjects do not. Graves' IgG-and TSH- induced IP formation is inhibited by blocking TSH receptor (TSHR) antibodies from hypothyroid patients with primary myxedema, as is the cAMP response; this suggests that the Graves' IgG are acting through the TSHR to induce both the cAMP and phosphatidyl-inositol 4,5- biphosphate signal cascades in FRTL-5 thyroid cells as in cells with recombinant TSHR. Optimal conditions for measuring the Graves' IgG- induced IP increase include a NaCl-free Hanks' Balanced Salt Solution (HBSS) buffer system and a P1 purinergic receptor agonist; the action of each is additive. Optimization by NaCl-free HBSS is similar to that observed in cAMP assays and is specific for TSH or Graves' IgG; thus, NaCl-free HBSS did not affect ATP-induced, and actually inhibited norepinephrine-induced, IP production in FRTL-5 cells. The P1 purinergic receptor agonist acts via receptor cross-talk, which also allows further optimization of cAMP assays. Thus, adenosine deaminase improves Graves' IgG-induced cAMP production by removing adenosine from the medium. Although NaCl-free HBSS improved TSH- or Graves' IgG- induced IP and cAMP production in cells with recombinant TSHR; the modulatory action of phenylisopropyladenosine was lost.

This article has been cited by other articles:

				J. Wortsman, P. McConnachie, K. Tahara, and L. D. Kohn Thyrotropin Receptor Epitopes Recognized by Graves' Autoantibodies Developing under Immunosuppressive Therapy J. Clin. Endocrinol. Metab., July 1, 1998; 83(7): 2302 - 2308. [Abstract] [Full Text]

				L. D. Kohn, K. Suzuki, W. H. Hoffman, D. Tombaccini, C. Marcocci, N. Shimojo, Y. Watanabe, N. Amino, B. Y. Cho, Y. Kohno, et al. Characterization of Monoclonal Thyroid-Stimulating and Thyrotropin Binding-Inhibiting Autoantibodies from a Hashimoto's Patient Whose Children Had Intrauterine and Neonatal Thyroid Disease J. Clin. Endocrinol. Metab., December 1, 1997; 82(12): 3998 - 4009. [Abstract] [Full Text] [PDF]

				R. Di Paola, C. Menzaghi, V. De Filippis, D. Corda, and A. Di Cerbo Cyclooxygenase-Dependent Thyroid Cell Proliferation Induced by Immunoglobulins from Patients with Graves' Disease J. Clin. Endocrinol. Metab., February 1, 1997; 82(2): 670 - 673. [Abstract] [Full Text] [PDF]