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.
Medizinische Klinik Innenstadt, Universität München, Germany.
A
A
Nolte
G
G
Bechtner
M
M
Rafferzeder
R
R
Gärtner
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