肾素系统在胰岛素抵抗性高血压中作用的探讨

Objective To study the possible mechanisms by which insulin resistanceindu ces hypertension and left ventricular hypertrophy from the aspect of renin-angio tensin-aldosterone system (RAAS). Methods The insulin-resistant hypertensive ra t (IRHR) model (n=13) was reproduced by feeding SD rats for 8 weeks on a high-su crose chow. SD rats (n=10) were studied as a control group. The elem ents in RAAS in plasma and myocardium were measured by radioimmunoassay and morphological ch anges were investigated. Results Blood pressure (Bp) in IRHR was higher than in control group. Serum insulin (INS), triglyceride, aldosterone(ALD),left ventric ular relative mass, renin activity(RA), angiotensin Ⅱ (Ang Ⅱ) in myocardium we r e higher in IRHR than in control group. Serum high-density lipoprotein (HDL-C) w as lower in IRHR. Plasma RA and Ang Ⅱ in IRHR were not statistically different f rom those in control group (P>0.05). Myocardial cellular hypertrophy and increas ed interstitial collagenous fibers were found in IRHR by optical microscopy and electronmicrograph. Conclusions High-sucrose feeding can induce insulin resista nce, hypertension and dyslipidemia in SD rats. Hypertension in IRHR is related t o insulin resistance and compensatory hyperinsulinemia. In this model hyperinsul inemia may have no or short-term effect on the level of circulatory RA and Ang Ⅱ, but plasma ALD and myocardial RA, Ang Ⅱ, which may be increased by hyperins uli nemia, may be the important factors that maintain the long-term high blood press ure. The formation of left ventricular hypertrophy in IRHR may be not only due t o high blood pressure, serum INS which is a direct proliferation-stimulating fac tor, but also to tissular RA, Ang Ⅱ which may be activated by hyperinsulinemia.

EVALUATION OF RENIN ANGIOTENSIN ALDOSTERONE SYSTEM IN INSULIN RESISTANT HYPERTENSION