Biology:Plummer effect

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Compensatory mechanisms preventing thyrotoxicosis in oversupply with iodine, including the Wolff-Chaikoff effect, the Plummer effect and the dehalogenase inhibition effect

The Plummer effect is one of several physiological feedforward mechanisms taking place in follicular cells of the healthy thyroid gland and preventing the development of thyrotoxicosis in situations of extremely high supply with iodine.[1]

History

In 1923 the American physician Henry Stanley Plummer discovered that high-dose iodine may be effective in the treatment of Graves’ disease.[2][3] Today, “Plummering”, i.e. therapy with Lugol's iodine solution, is one of several emergency measures in the management of severe thyrotoxicosis.[4]

Mechanism

Via the Plummer effect, a high iodine concentration inhibits the proteolysis of thyroglobulin and the release of pre-formed thyroid hormones from thyroid follicles.[5] Therefore, its mechanism differs from that of the Wolff–Chaikoff effect, where iodine inhibits the uptake of iodine in thyroid cells and the formation of thyroid hormones, and of the dehalogenase inhibition effect, where high iodine levels block deiodinases and other dehalogenases.[6][7]

The Plummer effect lasts about 7 to 10 days, but unlike the Wolff-Chaikoff effect, it isn't subject to an escape phenomenon.[8]

The three different mechanisms of high iodine response, the Plummer effect, the Wolff-Chaikoff inhibition effect, and the adaptive escape phenomenon, synergistically work together to fend off potentially harmful consequences of excess iodine load and ensure thyroid homeostasis.[1]

Clinical implications

Unlike the Wolff–Chaikoff effect, the Plummer effect does not prevent the thyroid from taking up radioactive iodine, e.g. in the case of nuclear emergencies. Therefore, "plummering" with high-dose iodine is only effective in a short time window after the release of radionuclides.[9] Wrong timing of iodine use may even increase the risk by triggering the Plummer effect.[10]

The Plummer effect is, however, helpful in the management of thyrotoxicosis, where the usage of Lugol’s solution helps to limit the release of thyroid hormones into the bloodstream.[4]

See also

References

  1. 1.0 1.1 Jing, Li; Zhang, Qiang (15 September 2022). "Intrathyroidal feedforward and feedback network regulating thyroid hormone synthesis and secretion". Frontiers in Endocrinology 13: 992883. doi:10.3389/fendo.2022.992883. PMID 36187113. 
  2. Plummer, HS (30 June 1923). "Results of administering iodin to patients having exophthalmic goiter". JAMA: The Journal of the American Medical Association 80 (26): 1955. doi:10.1001/jama.1923.02640530065026. 
  3. Loriaux, D. Lynn (March 2016). A Biographical History of Endocrinology. doi:10.1002/9781119205791.ch58. 
  4. 4.0 4.1 Reyes-Castano, John J.; Burman, Kenneth (2014). "Thyrotoxic Crisis: Thyroid Storm". Endocrine Emergencies: 77–97. doi:10.1007/978-1-62703-697-9_9. ISBN 978-1-62703-696-2. 
  5. Saller, B; Fink, H; Mann, K (1998). "Kinetics of acute and chronic iodine excess.". Experimental and Clinical Endocrinology & Diabetes 106 Suppl 3: S34-8. doi:10.1055/s-0029-1212044. PMID 9865552. 
  6. Solis-S, JC; Villalobos, P; Orozco, A; Delgado, G; Quintanar-Stephano, A; Garcia-Solis, P; Hernandez-Montiel, HL; Robles-Osorio, L et al. (January 2011). "Inhibition of intrathyroidal dehalogenation by iodide.". The Journal of Endocrinology 208 (1): 89–96. doi:10.1677/JOE-10-0300. PMID 20974636. 
  7. Hansson, M; Filipsson Nyström, H; Jansson, S; Lausmaa, J; Berg, G (2012). "Iodine Content and Distribution in Thyroid Specimens from Two Patients with Graves' Disease Pretreated with Either Propylthiouracil or Stable Iodine: Analysis Using X-Ray Fluorescence and Time-of-Flight Secondary Ion Mass Spectrometry.". Case Reports in Endocrinology 2012: 842357. doi:10.1155/2012/842357. PMID 22953073. 
  8. Nyström, Ernst; Berg, Gertrud E. B.; Jansson, Svante K. G.; Törring, Ove; Valdemarsson, Stig V. (2011). Thyroid disease in adults. Berlin: Springer. pp. 16. ISBN 9783642132629. 
  9. Zanzonico, PB; Becker, DV (June 2000). "Effects of time of administration and dietary iodine levels on potassium iodide (KI) blockade of thyroid irradiation by 131I from radioactive fallout.". Health Physics 78 (6): 660–7. doi:10.1097/00004032-200006000-00008. PMID 10832925. 
  10. Meristoudis, G; Ilias, I (June 2022). "Caveats in the use of potassium iodide for thyroid blocking.". European Journal of Nuclear Medicine and Molecular Imaging 49 (7): 2120–2121. doi:10.1007/s00259-022-05797-7. PMID 35403862.