The role of the primitive sea in the natural selection of iodides as a regulating factor in inflammation.

Iodides have many non-endocrine biologic effects, including a role they play in the physiology of the inflammatory response. Iodides when given systemically or applied locally increase the movement of granulocytes into areas of inflammation. They improve the phagocytosis of bacteria by granulocytes and the ability of granulocytes to kill bacteria. They alter native protein to make it more susceptible to enzymes produced by granulocytes. They increase glandular secretions and make mast cells more labile. They concentrate around tumors and granulomas in man and animals. They also move into areas of tissue injury. When iodide is redistributing around sites of tumors or injuries there is decreased thyroid uptake and decreased renal excretion. The multiple effects of iodides have suggested that iodide may have a physiological role in inflammation. Iodides were once used widely in medicine, especially before a cure for syphilis. Understanding the many known effects of iodides requires crossing multiple fields. The purpose of this paper is to propose that the rising iodide content of the primitive sea played a role in the natural selection of a system which helped the organism recover from tissue injury or invasion. As primative life forms underwent mutations those with a defense system more responsive to environmental factors, such as iodide, had the best chance of survival. It was important for a defense system to move to any point of surface injury. The diverse biologic effects of iodides suggest a very primative role. This effect was so important that it was later internalized so that today iodides are concentrated in the host around sites of injury or tumor growth.(ABSTRACT TRUNCATED AT 250 WORDS)