Biological characteristics of adenomatous nodules, adenomas, and hyperfunctioning nodules as defined by adenylate cyclase activity and TSH receptors

This study was designed to examine the functional characteristics of thyroid adenomas, adenomatous (colloid) nodules, hyperfunctioning nodules, and normal thyroid parenchyma with respect to the presence of TSH receptors, levels of adenylate cyclase, and the responsiveness of adenylate cyclase to specific stimuli, e.g., NaF (sodium fluoride), GTPγS [guanosine 5′-0-(3-thiotriphosphatate)], PGE1, and TSH. Aliquots of specimens from patients undergoing thyroidectomy [11 normal thyroids, 7 adenomas, 8 adenomatous (colloid) nodules, 5 hyperfunctioning nodules] were immersed in liquid nitrogen and stored at 90°C. Studies were performed on partially purified plasma membranes. Receptor binding of125I-TSH was quantitated and analyzed according to Scatchard. Adenylate cyclase activity was assayed in the same tissue fraction by conversion of (α-32P) ATP to cAMP.