褪黑素与血压昼夜节律的相关性研究

Circadian rhythm of melatonin and blood pressure changes in patients with essential hypertension

目的研究褪黑素（MLT）与血压昼夜节律的关系。方法选门诊、住院患者及健康查体者88例分为非杓型高血压组、杓型高血压组及对照组；行24小时动态血压监测；同期测定患者白昼和黑夜尿6羟基硫酸褪黑素（6-SMT）含量，并计算黑夜／白昼尿6-SMT比值。结果（1）非杓型高血压组的夜间收缩压、舒张压及平均动脉压下降率均低于杓型高血压组和对照组（P〈0．01）；杓型高血压组和对照组间差异无统计学意义（P〉0．05）。（2）各组患者的黑夜尿6-SMT含量高于白昼（P〈0．01）；非杓型高血压组的黑夜尿6-SMT含量和黑夜／白昼尿6-SMT比值低于杓型高血压组和对照组（P〈0．01）。（3）在各组内，各黑夜／白昼尿6-SMT比值与其组夜间血压下降率均存在正相关（P〈0．05）。结论血压节律呈现杓型分布的杓型高血压组和对照组，其MLT在黑夜分泌较多；非杓型高血压组MLT黑夜分泌明显减少，与血压昼夜节律异常存在密切关系。

Objective To observe the association between melatonin （MLT） secretion and blood pressure changes during 24 hours in hypertensive patients （HPT） with （dipping） or without （non-dipping） night time blood pressure reduction. Methods The 2A-hour blood pressure and urine 6-SMT （6-sulfatoxymelatonin, metabolism product of MLT in urine ） in the daytime and nighttime were measured in normal control subjects （ n = 20 ）, non-clipping HPT group （ n = 32 ） and dipping HPT group （ n = 36 ）. Results As expected, blood pressure reduction during the night was significantly lower in non-dipping HPT group compared to control and dipping HPT groups. Nighttime 6-SMT was significantly higher than daytime 6-SMT in all groups and nighttime urine 6-SMT levels and ratio of nighttime/daytime urine 6-SMT levels were significantly lower in non-clipping HPT group compared to control and dipping HPT groups （all P 〈 0. 01 ）. Moreover, ratio of nighttime/daytime urine 6-SMT levels are positively correlated blood pressure reduction during nighttime （ P 〈 0.05 ） in all groups. Conclusions Circadian rhythm of MLT secretion is maintained but nighttime MLT secretion was significantly reduced and related to disorders of circadian rhythm of blood pressure in non-dipping HPT group.