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KMID : 0378019890320120046
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New Medical Journal
1989 Volume.32 No. 12 p.46 ~ p.50
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Levels of Inorganic Ions and Urea in Renal Tissues of Rabbits
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Abstract
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It is well known that the concentrating mechanism of the mammalian kidney : es an osmotic gradient in the extracellular fluid of the medulla, increasing to high values toward the papillary tip.
The major extracellular solutes in renal papilla are urea and Na Cl. The sum of intr : cellular sodium and potassium concentration is lower than that of extracellular although ere are conflicting reports concerning the magnitude of osmotic gap.
The renal tubular cells cannot sustain any sizeable osmotic pressure differences across thier cell membranes. Also, the high levels of salts and urea are toxic to cellular enzy es. So, nonperturbing osmolytes must appear in the intracellular fluids of renal tubular cells.
The actions of these intracellular osmotic components are very complex. Especi. ly the kinds, the change in location and the conversion to other forms in these compon& is are principal interests in the urinary concentrating mechanisms in the kidney.
In an attempt to clarify the role of osmotic solutes in the kidney and to select the proper time for the sample preparation, we measured the levels of inorganic ions and urea ´ rabbit kidney tissues.
The levels of sodium and chloride ion, urea and osmolality of the medulla were high-r than those of the cortex, but there was no difference in the level of potassium ion betw, in the medulla and cortex. The sum of differences in sodium and chloride ion and urea .between the cortex and medulla was lower than the difference in osmolality.
Although the levels of inorganic ions, urea and osmolality were changed with the .rogress of time, there were no significant changes in those levels.
The results of this experiment suggest that the levels of inorganic ions, urea and osolality are not changed with the progress of time and the sodium and chloride ion and urea have contributed to the high osmolality in the medulla.
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KEYWORD
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