COMPARATIVE ASPECTS OF IODINE CONSERVATION IN MAMMALS

1. Comparative aspects of iodine conservation in mammals were studied on the basis of published data on kidney and thyroid weights and funct ion. 2. Very small mammals possessed an efficient reabsorption of iodi de to compensate for the high glomerular filtration rate (GFR). 3. Hum ans and mammals of a similar and larger size had ''lost'' the ability to reabsorb iodide efficiently. 4. Very large mammals are protected ag ainst renal loss of iodide due to the relatively low GFR. 5. Thyroid w eights in relation to body weight were highest in humans suggesting th at humans and other mammals of a similar size are especially susceptib le to iodine deficiency.