Urine Concentration and the Adaptation of Renal Medullary Cells to Hypertonicity

Kim, Dong-Un

doi:2007.11.2.145

J Korean Soc Pediatr Nephrol > Volume 11(2); 2007 > Article

J Korean Soc Pediatr Nephrol 2007;11(2): 145-151. doi: https://doi.org/10.3339/jkspn.2007.11.2.145

소변농축과 장력 스트레스에 대한 콩팥 수질 세포들의 적응

김동언

가톨릭대학교 의과대학 소아과학교실

Urine Concentration and the Adaptation of Renal Medullary Cells to Hypertonicity

Dong-Un Kim

Department of Pediatrics, College of Medicine, The Catholic University of Korea

ABSTRACT

Hypertonicity (hypernatremia) of extracellular fluid causes water movement out of cells, while hypotonicity(hyponatremia) causes water movement into cells, resulting in cellular shrinkage or cellular swelling, respectively. In most part of the body, the osmolality of extracellular fluid is maintained within narrow range($285-295 mOsm/kgH_2O$) and some deviations from this range are not problematic in most tissue of the body except brain. On the other hand, the osmolality in the human renal medulla fluctuates between 50 and $1,200 mOsm/kgH_2O$ in the process of urine dilution and concentration. The adaptation of renal medullary cells to the wide fluctuations in extracellular tonicity is crucial for the cell survival. This review will summarize the mechanisms of urine concentration and the adaptation of renal medullary cells to the hyper tonicity, which is mediated by TonEBP transcription factor and its target gene products(UT-A1 urea transporter etc.).

Key words: Hypertonicity | Urine concentration | TonEBP transcription factor | UT-A1 urea transporter