Determining the Effect of L-arginine and Physical Activity on the Plasma Levels of Endothelin-1 and Tissue Inhibitor of Metalloproteinase-1 in Postmenopausal Women with Hypertension

Abstract

Background and Objectives Exercise and L-arginine supplementation are known as effective strategies for treating hypertension. The aim of the present study was to determine the effect of aerobic exercise and L-arginine consumption on tissue inhibitor of metalloproteinase-1 (TIMP-1) and endothelin-1 (ET-1) levels in postmenopausal women with hypertension. Subjects and Methods In this quasi-experimental research, 40 postmenopausal women with hypertension were divided into four equal groups including exercise, exercise + L-arginine, L-arginine, and placebo groups. Interventions of aerobic exercise (60-75% of maximum heart rate) and L-arginine supplementation (6 g/day) were completed for 12 weeks. Forty-eight hours after the last intervention session, blood samples similar to the pre-test were collected to measure TIMP-1 and ET-1 levels using ELISA method. Results Plasma ET-1 levels in the training and training + L-arginine groups were significantly reduced compared to the placebo and L-arginine groups. In addition, plasma TIMP-1 increased significantly in the exercise group and exercise + L-arginine group compared to the placebo group. No synergistic effect was observed on TIMP-1 and ET-1 levels, despite the greater effect of exercise combined with L-arginine supplementation. Conclusion According to the results of the present research, improved blood pressure in adaptation to aerobic exercises is associated with reduced ET-1 and increased TIMP-1. L-arginine supplement, either alone or in combination with aerobic exercise, has no significant effect on TIMP-1 and ET-1 changes.