Effect of L-arginine on Na+,K+-ATPase activity in rat aorta endothelium.
The effect of L-arginine on the Na+,K+-ATPase activity in rat aorta endothelium was studied at its physiological concentrations in the range of 10(-6)-10(-3) M. The enzyme activity was 35.5% increased by low concentrations of L-arginine (<or=10(-5) M) and its activity was 32.3-37.1% decreased at the L-arginine concentrations of 10(-4)-10(-3) M. A similar inhibition (by 34.5-42.8%) was also found in the presence of a NO-donor nitroglycerol (10(-4)-10(-3) M). An optical isomer of L-arginine, D-arginine, at the concentrations of <or=10(-5) M also increased the enzyme activity by 37.1%, but its inhibiting effect was much less pronounced and was 15.7% at the D-arginine concentration of 10(-3) M. An inhibitor of NO-synthase, L-NAME (NG-nitroarginine, methyl ester), failed to inhibit Na+,K+-ATPase. However, the presence of L-NAME abolished the inhibition of Na+,K+-ATPase by high concentrations of L-arginine. Thus, the effect of L-arginine on the endothelial Na+-pump depended on its concentration, and it is suggested that the enzyme inhibition by high concentrations of L-arginine should be associated with activation of the endogenous synthesis of NO.
Akopova
O V
OV
Bogomolets Institute of Physiology, National Academy of Sciences of Ukraine, Kiev, 01024, Ukraine. circul@serv.biph.kiev.ua
Kharlamova
O N
ON
Vavilova
G L
GL
D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000201:enzymology; D001120:Arginine / Q000737:chemistry / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000201:enzymology*; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000737:chemistry / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D005996:Nitroglycerin / Q000737:chemistry / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013237:Stereoisomerism; D013329:Structure-Activity Relationship
D004791:Enzyme Inhibitors; D009569:Nitric Oxide; D001120:Arginine; D019001:Nitric Oxide Synthase; D000254:Sodium-Potassium-Exchanging ATPase; D005996:Nitroglycerin; D019331:NG-Nitroarginine Methyl Ester