Although it has been well established that thyroid hormones increase β-adrenergic receptors of various tissues in the animal studies, there are controversies about the β-adrenergic receptor changes of human mononuclear cells and polymorphonuclear cells.
The present study was performed to analyze the change of β-adrenergic receptor of those cells according to the thyroid functional status and to evaluate their usefulness in assessment of sympathetic hyperactivity. We measured [3H]-dihydroalprenolol binding to circulating mononuclear and polymorphonuclear cells from 18 patients with hyperthyrodism, 7 with hypothyroidism, 8 with euthyroid goiter and 21 normal controls.
Only with polymorphonuclear cells the receptor concentration was significantly higher (P<0.01) in hyperthyroidism (46.07±4.78 fmol/mg protein) than in the normal control (28.42±2.06 fmol/mg protein) and the affinity constants of both cells were comparable to normal control values. And serum concentrations of T3 were not correlated well with the changes of receptor concentrations in hyperthyroidism. The patients with hypothyroidism and euthyroid goiter showed no significant difference in the receptor concentration and the affinity constants with both cell binding assays.
These results indicate that thyroid hormones increase the receptor concentration in polymorphonuclear cells which might be responsible for the symptoms of sympathetic hyperactivity and the polymorphornuclear cells are useful for β-adrenergic receptor assay.