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International Journal of Medical Sciences

.: Home > International Journal of Medical Sciences > 2011 > Volume 8 Number 2 > Harry G. Preuss1ƒx, Bobby Echard1, Eiji Yamashita2, Nicholas V. Perricone3

High Dose Astaxanthin Lowers Blood Pressure and Increases Insulin Sensi-tivity in Rats: Are These Effects Interdependent?

Harry G. Preuss1ƒx, Bobby Echard1, Eiji Yamashita2, Nicholas V. Perricone3
1. Georgetown University Medical Center, Department of Biochemistry, Washington, D.C. 20057, USA 2. Life Science Division, Fuji Chemical Industry Co., Ltd., Toyama 930-0397, Japan 3. Michigan State University College of Human Medicine, East Lansing, MI 48824-136, USA
Abstract :

The present investigation in Sprague-Dawley rats (SD) was designed to examine effects of astaxanthin (Asta) at different doses on elevated blood pressure (BP) and glucose-insulin perturbations produced by heavy sucrose ingestion. We also examined effects of Asta on BP during restraint stress. SD were divided into six groups each containing eight rats. All SD ate a basic diet of ground regular rat chow with sucrose added at 30% w/w. The Control group received only the basic diet containing added sucrose, while the other five groups each re-ceived the same diet with added test material: captopril, (30 mg/Kg), pioglitazone (15.0 mg/Kg), low Asta (25 mg/Kg), medium Asta (50 mg/kg) or high Asta (100 mg/Kg). Many tests were carried out to examine the mechanisms behind the effects of Asta on BP (serum ACE activity, losartan challenge, and LNAME challenge) and the glucose-insulin system (glucose tolerance, HOMA measurement, and insulin challenge). In SD, a relatively low dose of Asta decreased SBP, but produced no major changes in the glucose-insulin system simulating re-sults from a previous study using Zucker Fatty Rats. Increasing the dose of Asta resulted in both a lowering of elevated systolic BP and enhanced insulin sensitivity determined by many different estimations. BP lowering was consistent with changes in the renin-angiotensin (RAS) and nitric oxide (NO) systems. At the examined doses of each, captopril lowered BP in SD without influencing glucose-insulin metabolism, whereas pioglitazone favorably affected glu-cose-insulin metabolism while showing essentially no effects on BP. Accordingly, Asta bene-ficially affects both sucrose-induced elevations of BP and insulin resistance at relatively high doses in SD. Also, Asta at higher doses lessens restraint stress, whereas, captopril and pioglitazone did not at the doses examined, even though they influenced the BP and glu-cose-insulin systems respectively.

Keywords :
Astaxanthin, BP effect, Insulin resistance, Restraint stress, renin-angiotensin system

Date Deposited : 04 Jul 2011 10:42

Last Modified : 04 Jul 2011 10:42

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Volume 8, Number 2, - 2011 , ISSN 1449-1907

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