Interleukin-1 beta (IL-1 beta) binds to intact porcine thyroid follicles, decreases iodide uptake but has no effect on cAMP formation or proliferation.
Interleukin-1 beta (IL-1 beta) is known to be involved in autoimmune thyroiditis. Since the results of different in vitro-studies on the effect of IL-1 on thyrocytes are controversial, our aim was to investigate the existence of specific binding sites for IL-1 beta and its influence on specific functions and growth of isolated porcine thyroid follicles ex vivo with a preserved iodide metabolism. For binding studies isolated thyroid follicles were incubated with 125I-IL-1 beta (213.5 nCi/ml) and with increasing concentrations of unlabelled IL-1 beta (0.06-11.5 nmol/l) for 24 h at 4 degrees C. The dissociation constant Kd was 0.85 x 10(-10) mol/l and about 800 binding sites per cell were calculated. IL-1 beta (10 U/ml) decreased basal and TSH-stimulated iodide uptake and organification after an incubation time of 45 min to 6 h without any influence on cAMP-formation. In addition, after 40 h of incubation IL-1 beta dose-dependently increased T3-secretion, followed by a decrease during simultaneous TSH-stimulation, whereas there was no effect on T4-secretion. In contrast to these functional effects IL-1 beta showed no influence on the growth of thyroid follicles, so that the cytokine cannot be made responsible for goiter growth in thyroid diseases by directly influencing thyroxytes.
Nolte
A
A
Medizinische Klinik Innenstadt, Universität München, Germany.
Bechtner
G
G
Rafferzeder
M
M
Gärtner
R
R
D000818:Animals; D002455:Cell Division / Q000187:drug effects; D000242:Cyclic AMP / Q000096:biosynthesis*; D004247:DNA / Q000378:metabolism; D007375:Interleukin-1 / Q000493:pharmacokinetics* / Q000494:pharmacology; D007454:Iodides / Q000493:pharmacokinetics*; D007457:Iodine Radioisotopes; D009924:Organ Culture Techniques; D017472:Receptors, Interleukin-1 / Q000378:metabolism; D013552:Swine; D013961:Thyroid Gland / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D013963:Thyroid Hormones / Q000378:metabolism; D013972:Thyrotropin / Q000378:metabolism; D014284:Triiodothyronine / Q000378:metabolism
D007375:Interleukin-1; D007454:Iodides; D007457:Iodine Radioisotopes; D017472:Receptors, Interleukin-1; D013963:Thyroid Hormones; D014284:Triiodothyronine; D013972:Thyrotropin; D004247:DNA; D000242:Cyclic AMP