[Beta-adrenergic receptors and cAMP production in the lymphocytes of patients with differentiated carcinoma of the thyroid gland during hypothyroidism and euthyroidism].

Beta-adrenergic receptors and production of cyclic adenosine monophosphate (cAMP) was investigated in peripheral lymphocytes of patients with differentiated thyroid carcinoma in hypothyroidism and euthyroidism, following therapy with 131I and suppression with thyroid hormones. After 131I therapy of patients with differentiated thyroid carcinoma and suppression by means of thyroid hormones, when the patients became euthyroid, the authors found a significantly lower maximal binding capacity Bmax on lymphocytes, as compared with the same patients before radiotherapy when the patients were hypothyroid. The basic cAMP content in patients with euthyroidism was higher, as compared with hypothyroid patients, the difference being at the borderline of significance (p less than 0.06). In vitro stimulation of cAMP formation by lymphocytes using the beta-adrenergic agonist isoprenaline was similar in hypo- and euthyroid patients and did not change in the course of treatment. When expressed in per cent, the stimulation of cAMP formation during euthyroidism was rather lower. Stimulation of cAMP formation by forskoline, an activator of adenylate cyclase was significantly higher in euthyroidism. Simultaneous addition of isoprenaline and forskoline to the incubation medium with lymphocytes produced an additive effect with markedly higher stimulation in euthyroidism. The reduced maximum binding capacity for 3H-dihydroalprenolol (3H-DHA) in euthyroid patients is discussed with regard to the probable influence of the basic disease, participation of radiation and the possible influencing of the immune system on changes in the number and activity of the patients' receptor system.