Cellular response to osmotic stress in the renal medulla

摘要: Cells of the renal medulla, which are exposed under normal physiological conditions to widely fluctuating extracellular solute concentrations, respond hypertonic stress by accumulating organic osmolytes glycerophosphorylcholine (GPC), betaine, myo-inositol, sorbitol and free amino acids. Increased intracellular contents these achieved a combination increased uptake (myo-inositol betaine) synthesis (sorbitol, possibly GPC), decreased degradation (GPC) reduced osmolyte release. In medulla concentrating kidney, accumulation osmolytes, do not perturb cell function even at high allows maintenance ”normal” concentrations inorganic electrolytes. Adaptation decreasing e.g. diuresis, is primarily activation pathways allowing efflux secondarily inactivation production (sorbitol) (betaine, myo-inositol) stimulation (GPC). Apart from modulation content, osmolality-dependent reorganization cytoskeleton expression specific proteins (heat shock proteins) may be further, as yet poorly characterized, components regulatory systems involved in adaptation medullary cells osmotic stress.