Regulation of blood pressure and glucose metabolism induced by L-tryptophan in stroke-prone spontaneously hypertensive rats

Ardiansyah Ardiansyah,Takuya Koseki,Hitoshi Shirakawa,Yuto Inagawa,Michio Komai

doi:10.1186/1743-7075-8-45

Abstract

BackgroundAmino acids have been reported to act as modulators of various regulatory processes and to provide new therapeutic applications for either the prevention or treatment of metabolic disorders. The purpose of the present study is to investigate the effects of single oral dose administration and a continuous treatment of L-tryptophan (L-Trp) on the regulation of blood pressure and glucose metabolism in stroke-prone spontaneously hypertensive rats (SHRSP).MethodsFirst, male 9-week-old SHRSP were administered 100 mg L-Trp·kg-1 body weight in saline to the L-Trp group and 0.9% saline to the control group via a gastric tube as a single oral dose of L-Trp. Second, three groups of SHRSP were fed an AIN-93M-based diet supplemented with L-tryptophan (L-Trp) (0, 200, or 1000 mg·kg-1 diet) for 3 weeks as continuous treatment of L-Trp.ResultsSingle oral dose administration of L-Trp improved blood pressure, blood glucose, and insulin levels. Blood pressure, blood glucose, and insulin levels improved significantly in the L-Trp treatment groups. The administration of L-Trp also significantly increased plasma nitric oxide and serotonin levels.ConclusionL-Trp by both single oral dose administration and continuous treatment improves glucose metabolism and blood pressure in SHRSP.

Highlights

Our modern lifestyle is prone to overnutrition and lack of physical activity, which dramatically increases the incidence of metabolic disorders, including diseases associated with obesity, diabetes mellitus, dyslipidemia, and hypertension [1]
Much effort is being invested in detecting bioactive compounds in foods that can decrease the risk of metabolic disorders, including dietary antioxidants such as vitamin E, vitamin C, carotenoids, and polyphenols, which are known to decrease the risk factors of cardiovascular diseases [2]
The purpose of the present study is to investigate the effects of single oral dose administration and a continuous treatment of L-tryptophan (L-Trp) on the regulation of blood pressure and glucose metabolism in stroke-prone spontaneously hypertensive rats (SHRSP), an animal model of hypertension-related disorders and insulin resistance in humans [14,15]

Summary

Introduction

Our modern lifestyle is prone to overnutrition and lack of physical activity, which dramatically increases the incidence of metabolic disorders, including diseases associated with obesity, diabetes mellitus, dyslipidemia, and hypertension [1]. Recent research has demonstrated that certain amino acids, such as L-tryptophan (L-Trp), can regulate physiological processes and may be the basis for novel therapeutics to prevent or treat chronic diseases. Amino acids have been reported to act as modulators of various regulatory processes and to provide new therapeutic applications for either the prevention or treatment of metabolic disorders. The purpose of the present study is to investigate the effects of single oral dose administration and a continuous treatment of Ltryptophan (L-Trp) on the regulation of blood pressure and glucose metabolism in stroke-prone spontaneously hypertensive rats (SHRSP). Three groups of SHRSP were fed an AIN-93M-based diet supplemented with L-tryptophan (L-Trp) (0, 200, or 1000 mg·kg-1 diet) for 3 weeks as continuous treatment of L-Trp

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Results