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Objective To investigate the effect of insulin on D_5 dopamine receptor expression and function in renal proximal tubule (RPT).Methods Immortalized RPT cells and D_5 receptor transfected HEK293 (HEK-D_5) cells were used in the study to investigate the effect of insulin on D_5 receptor expression and function,and those effects were compared in RPT cells from Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR). The function of D_5 receptor was determined by measurement of the Na~+-K~+-ATPase activity in HEK-D_5 cells. Results Insulin increased D_5 receptor protein expression in a concentration and time-dependent manner in WKY RPT cells,but not in SHR.The basal level of D_5 receptor expression was higher in WKY cells than that in SHR cells. Stimulation with fenoldopam(D_1-like dopamine receptor agonist) inhibited the Na~+-K~+-ATPase activity;pretreat- ment with insulin increased the inhibitory effect of fenoldopam on Na~+-K~+-ATPase activity in HEK-D_5 cells. Conclusion The abnormal regulation of insulin on D_5 receptor expression and function might be involved in the path- ogenesis of essential hypertension.
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Objective To test the role of a bioartificial kidney which consisted of a continuous vein-vein hemofiltration (CVVH) system and renal proximal tubule cells (PTCs)device, also called the renal tubule assist device (RAD),in endotoxin shock.Methods Female crossbred pigs 25 to 30 kg received with 3×1011 bacteria / kg body weight of E.coli intraperitoneally followed by treatment with a sham RAD without cells (n=7) or a RAD with cells (n=7). Data on blood pressure, cardiac output, renal blood flow and systemic marker of inflammation (IL-6) were measured.Results Cardiac outputs and renal blood flows were higher in the RAD group with cells than in the sham RAD group after E.coli infusion (P＜0.05). Plasma IL-6 levels were lower in the cell RAD group than in the sham RAD group after bacterial administration (P＜0.05). A significant difference on survival time was also observed between the two groups,with(9.07 ± 0.88) h in the cell RAD group vs. (5.10 ± 0.46)h in the sham RAD group, P＜ 0.01.Conclusion The bioartificial kidney containing PTCs can improve cardiovascular function,reduce cytokine levels,and prolong survival time.