Weyer C, Pratley R E, Snitker S, Spraul M, Ravussin E, Tataranni P A
Clinical Diabetes and Nutrition Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, Arizona, USA.
Hypertension. 2000 Oct;36(4):531-7. doi: 10.1161/01.hyp.36.4.531.
Hyperinsulinemia and increased sympathetic nervous system (SNS) activity are thought to be pathophysiological links between obesity and hypertension. In the present study, we examined the relation among heart rate (HR), blood pressure (BP), and percent body fat (hydrodensitometry or DEXA), fasting plasma insulin concentration, and muscle sympathetic nerve activity (MSNA, microneurography) in male, normotensive whites (n=42) and Pima Indians (n=77). Pima Indians have a high prevalence of obesity and hyperinsulinemia but a relatively low prevalence of hypertension. Compared with whites, Pima Indian men had a higher percent body fat (28% versus 21%) and higher fasting insulin concentrations (210 versus 132 pmol/L) but lower MSNA (27 versus 33 bursts/min) (all P<0.001). In both ethnic groups, HR and BP were positively related to percent body fat and MSNA, and both were significant independent determinants of HR and BP in multiple regression analyses. However, MSNA was positively related to percent body fat and the fasting insulin concentration in whites (r=0.60 and r=0.47, both P<0.01) but not in Pima Indians (r=0.15 and r=0.03, NS) (P<0.01 for ethnic differences in the slope of the regression lines). These results confirm the physiological importance of the SNS in normal BP regulation but indicate that the roles of hyperinsulinemia and increased SNS activity as mediators for the relation between obesity and hypertension can differ between different ethnic groups. The lack of an increase in SNS activity with increasing adiposity and insulinemia in Pima Indians may contribute to the low prevalence of hypertension in this population.
高胰岛素血症和交感神经系统（SNS）活动增加被认为是肥胖与高血压之间的病理生理联系。在本研究中，我们检测了正常血压的白人男性（n = 42）和皮马印第安人男性（n = 77）的心率（HR）、血压（BP）、体脂百分比（水下密度测定法或双能X线吸收法）、空腹血浆胰岛素浓度以及肌肉交感神经活动（MSNA，微神经ography）之间的关系。皮马印第安人肥胖和高胰岛素血症的患病率较高，但高血压的患病率相对较低。与白人相比，皮马印第安男性的体脂百分比更高（28%对21%），空腹胰岛素浓度更高（210对132 pmol/L），但MSNA更低（27对33次/分钟）（所有P<0.001）。在两个种族群体中，HR和BP均与体脂百分比和MSNA呈正相关，并且在多元回归分析中，二者均是HR和BP的显著独立决定因素。然而，MSNA在白人中与体脂百分比和空腹胰岛素浓度呈正相关（r = 0.60和r = 0.47，均P<0.01），但在皮马印第安人中并非如此（r = 0.15和r = 0.03，无统计学意义）（回归线斜率的种族差异P<0.01）。这些结果证实了SNS在正常血压调节中的生理重要性，但表明高胰岛素血症和SNS活动增加作为肥胖与高血压关系的介导因素，在不同种族群体中可能有所不同。皮马印第安人脂肪增多和胰岛素血症增加时SNS活动未增加，这可能是该人群高血压患病率较低的原因。
