Chaikoff

Wohl-Aue synthesis Wohlwill process Wolff-Chaikoff effect... 

Iodide and Other Inorganic Anions. When large doses of iodide ion are administered, a transient inhibition of synthesis and release of the thyroid hormones is brought about by the so-called Wolff-Chaikoff effect. 

Scott, K. G., Overstreet, R., Jacobson, L., Hamilton, J. G., Fisher, H., Crowley, J., Chaikoff, I. L., Entenman, C., Fishler, M., Barger, A. J. AND Loomis, F. (1947). The Metabolism of Carrier-Free Fission Products in the Rat, Report No. MDDC-1275 (National Technical Information Service, Springfield, Virginia). 

Al. Abraham, S., Cady, P., and Chaikoff, I. L., Effect of insulin in vitro on pathways of glucose utilization other than Embden-Meyerhof in rat mammary gland, y. Biol. Chem. 224, 955-962 (1957). 

Wittig reaction, 2 64-65, 19 65 Wobbe Number, 12 378-379 Wohl-Aue synthesis, 2 787 Wohlwill refining process, 22 647 Wolff-Chaikoff effect, 14 373 Wolff-Kichner reduction, 13 569-570,... 

The thyroid gland also regulates its uptake of iodide and thyroid hormone synthesis by intrathyroidal mechanisms that are independent of TSH. These mechanisms are primarily related to the level of iodine in the blood. Large doses of iodine inhibit iodide organification (Wolff-Chaikoff block, see Figure 38-1). In certain disease states (eg, Hashimoto s thyroiditis), this can inhibit thyroid hormone synthesis and result in hypothyroidism. Hyperthyroidism can result from the loss of the Wolff-Chaikoff block in susceptible individuals (eg, multinodular goiter). 

Two neonates who had been given intravenous amiodarone as fetuses at 26 and 29 weeks and whose mothers had also taken it orally developed hypothyroidism (83). The authors suggested that low dietary iodine intake by the mothers may have contributed, by enhancing the Wolff-Chaikoff effect. 

Although cholesterol is accepted as the major precursor of steroid hormones as a result of side-chain cleavage to pregnenolone (see below), research over the past decade or so has focused on the mechanisms by which steroidogenic tissues obtain cholesterol. It should be borne in mind that such tissues require cholesterol, not only for steroid synthesis but also for membrane synthesis, and hence require more of the precursor sterol than other tissues. Morris and Chaikoff [1] showed that the bulk of rat adrenal cholesterol was derived from circulating cholesterol, and later work revealed a similar state of affairs in humans. 

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