The metabolism of bromine in mammals.

The aim of the present investigation was to determine whether bromine has a physiological role in the mammalian body. For this purpose the following investigations were carried out: (1) Bromide levels and its possible binding to protein in the sera of human subjects and guinea pigs were examined. No protein bound bromine was found in either. The bromide ratios of red blood cells to serum and of the serum to C.S.F. were determined. The concentration varies between cells and serum in blood, but only to a limited extent, and is higher than in C.S.F. The blood concentration is influenced by diet. The bromide/chloride ratio in both serum and C.S.F. were also measured and was found to be different. The serum bromide levels in a group of schizophrenic patients fell within the lower half of the normal range. This was shown to be due to the dietary factor. (2) The bromide content in various tissues of man (including various regions of one human brain), of guinea pigs, of rabbits and of rats were examined by a chemical method. A radio-isotope method was also used but only in guinea pigs. The results showed that no tissue concentrates bromide preferentially, with the exception of the stomach (measured only in guinea pigs). No protein bound bromine was found in the pituitary. The prolonged administration of varying amounts of bromide to guinea pigs showed that there was a progressive accumulation of bromide in all organs studied, the highest being in the serum. The addition of fluoride to the drinking water of guinea pigs significantly decreased the bromide level in all tissues studied. This suggests that fluoride can displace bromide in tissues. (3) The effect of bromide and fluoride on thyroid. function was investigated, and the results suggest that bromide may stimulate and fluoride depress the production of thyroid hormone. (4-) The rate of bromide excretion in humans was investigated using both radioisotopic and chemical techniques; the results showed that there was very little excretion during the first 24 hours (approximately 2 percent) and that the average biological half-life of bromide is approximately 6 days. Studies also indicated that chloride is excreted. preferentially to bromide by the kidney. It was found that bromide is excreted. at a reduced rate during the night. This diurnal rhythm of bromide excretion follows very closely that of chloride and sodium. There was no definite relationship between urinary volume and bromide excretion. (5) Prolonged administration of bromide and. fluoride to guinea pigs showed no significant effect on blood components, such as sodium, potassium, acetyl cholinesterase and alanine amino transferase (G.P.T).