Involvement of certain aminoacids in the cardioprotective actions in cholesterol-fed rats

ABSTRACT

The effects of long-term administration of cholesterol on free amino acids in the heart of rats were investigated, using an automatic LKB Amino Acid Analyzer [Biochrom Ltd., Cambridge, England]. Feeding cholesterol intake 100 mglkg/day for 20 weeks significantly elevates the contents of aspartate from 135 +/- 014 to 187 +/- 008 [micro] mol/100 g wet tissues [P< 0.005], glutamine from 204 +/- 017 to 293 +/- 025 [micro] mol/100 g wet tissues [P< 0.01], ornithine from 7 +/- 001 to 114 +/- 008 [micro] mol /100 g wet tissues [P< 0.001], histidine from 44 +/- 005 to 79 +/- 008 [micro] mol/100 g wet tissues [P< 0.005] and arginine from 74 +/- 009 to 390 +/- 010 [micro] mol/100 g wet tissues [P< 0.001] in the heart. These increases are concomitant with slight increase in cardiac taurine from 1891 +/- 156 to 2064 +/- 136. However, this increase was insignificant [P > 0.05]. These alterations in the contents of the amino acids present in the heart were associated with a significant elevation in the plasma Gamma Glutamyl transferase [[gamma] GT] activity. It is suggested that mobilization of the protective amino acids in the cardiac tissue indicates that there are interaction mechanisms between cholesterol intake and these certain amino acids that are considered as factors for generating metabolic events, which may play a physiological function in the protection of myocardium muscle from the action of cholesterol. Thus, under pathological conditions, there is an imbalance between these interaction mechanisms which enhance risk for atherosclerosis and coronary heart disease