Thyroid-Stimulating Hormone (TSH) Binding to Extrathyroidal Human Tissues: TSH and Thyroid- Stimulating Immunoglobulin Effects on Adenosine 3′,5′- Monophosphate in Testicular and Adrenal Tissues*

Abstract

Binding of [125I]bovine TSH to human thyroid, testicular, fat, adrenal, liver, kidney, pancreas, and lung cell membranes has been studied. The first four tissues were found to have comparable high affinity constant values; the rest of the tissues lacked high affinity sites. With the exception of fat tissue, the capacities of the high affinity sites of the first four tissues were similar. Bovine TSH concentrations of 100-20,000 microIU/ml stimulated increased cAMP production in human cryopreserved testicular slices. Forty percent of the specimens of thyroid-stimulating immunoglobulin (TSI) from Graves' disease sera also increased human testicular cAMP production. In addition, bovine TSH caused a significant rise in cAMP in the whole decapsulated rat testis. Twenty-five percent of the TSI specimens tested also induced such responses. The rat adrenal gland responded with increased cAMP production to concentrations of 1,000 microU/ml bovine TSH. The physiological significance of high affinity bovine TSH and TSI binding and subsequent cAMP production in nonthyroidal tissues in not known. However, since these stimulators are present in hypothyroidism and hyperthyroidism, respectively, it is possible that the pathophysiological effects of this binding could be of some importance.