Effect of Insulin on D_5 Dopamine Receptor Expression and Function in Renal Proximal Tubule Cells / 中华高血压杂志

ABSTRACT

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.