BACKGROUND L-arginine is the common substrate for the two isoforms of arginase. Arginase I, highly expressed in the liver and arginase II mainly expressed in the kidney. Arginase I-producing myeloid derived suppressor cells have been shown to inhibit T-cell function by the depletion of L-arginine. On the other hand, arginase II has been detected in patients with cancer and is thought to metabol...

An enzyme which condenses acetyl-L-leucyl-L-leucine and L-arginine into acetyl-L-leucyl-L-leucyl-L-leucyl-L-arginine (leupeptin acid) was partially purified from a cell extract of Streptomyces roseus MA839-A1. With respect to this catalytic activity, the enzyme showed the following characteristics: ATP is essential; optimum pH is 9.5; the activity is inhibited either by EDTA or pyrophosphate or...

The present study was designed to determine the efficiency of translocation of short polymers of arginine into vascular smooth muscle cells (VSMC) and to determine their effect on nitric oxide (NO) synthesis. Immunostaining revealed that heptamers of L-arginine (R7) rapidly translocated into the VSMC. This rapid transport was not observed with shorter polymers of L-arginine (R5) nor heptamers o...

AIMS Growing evidence suggests that arginase misregulation plays a key role in the pathophysiology of essential hypertension. In the present study, we investigated the potential cardiovascular therapeutic effects of a long-term treatment with an arginase inhibitor in adult spontaneously hypertensive rats (SHR) with fully developed hypertension. METHODS AND RESULTS Treatment of 25-week-old SHR...

In recent years it has become apparent that removal of apoptotic cells (AC) by professional phagocytes alters the macrophage phenotype. This change is characterized by attenuated proinflammatory cytokine expression and NO production, which mechanistically remained unexplained. With the intention to explore molecular mechanisms underlying reduced NO formation, we showed that NO production in IFN...

The effects of nitric oxide (NO) produced by cardiac inducible NO synthase (iNOS) on myocardial injury after oxidative stress were examined. Interleukin-1β induced cultured rat neonatal cardiac myocytes to express iNOS. After induction of iNOS,l-arginine enhanced NO production in a concentration-dependent manner. Glutathione peroxidase (GPX) activity in myocytes was attenuated by elevated iNOS ...

A deficient L-arginine-nitric oxide system is implicated in cortisol-induced hypertension. We investigate whether abnormalities in L-arginine uptake contribute to this deficiency. Eight healthy men were recruited. Hydrocortisone acetate (50 mg) was given orally every 6 hours for 24 hours after a 5-day fixed-salt diet (150 mmol/d). Crossover studies were performed 2 weeks apart. Thirty millilite...

Methylated arginine analogues are often used as probes of the effect of nitric oxide; however, their specificity is unclear and seems to be frequently overestimated. This study analyzed the effects of NG-methyl-L-arginine (L-NMMA) on the endothelium-dependent release of vascular superoxide radicals triggered by increased flow. Plasma ascorbyl radical signals measured by direct electron paramagn...