Pharmacokinetic Aspects of Inorganic Nitrate Ingestion in Man

Cortas, Nadim; Wakid, N W

doi:10.1111/j.1600-0773.1991.tb01221.x

Cited by 47 publications

(39 citation statements)

References 14 publications

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“…20 Therefore an impairment of renal function may cause an increase in nitrite/nitrate. Our observation that the concentration of nitrite/nitrate was higher in the renal dialysis patients than in the normal subjects supports previous findings.…”

Section: Discussionmentioning

confidence: 99%

Reduced production of nitric oxide during haemodialysis

Sumino

Sato

Sakamaki³

et al. 1999

J Hum Hypertens

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Objective: To examine the influence of systemic nitric oxide (NO) synthesis on blood pressure in patients with chronic renal failure undergoing haemodialysis, since nitric oxides are susceptible to renal excretion or are dialysed, a different indicator that is unaffected by renal function, such as the level of exhaled NO was evaluated. We examined the levels of the endogenous NO before and after a haemodialysis session. Design and methods: We evaluated the serum concentrations of nitrite/nitrate and the rate of nitric oxide release into exhaled air in 10 patients with hypertension who were receiving maintenance haemodialysis. Results: The serum concentrations of nitrite/nitrate before haemodialysis were significantly higher than those in 10 normal controls (183 ؎ 151 M vs 42 ؎ 17 M, P Ͻ 0.05). These levels decreased signifi-

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Section: Discussionmentioning

confidence: 99%

Reduced production of nitric oxide during haemodialysis

Sumino

Sato

Sakamaki³

et al. 1999

J Hum Hypertens

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“…The detection of the serum nitrite and nitrate levels as an index of NO production was based on the Griess reaction. 18) Total nitrite was measured at 540 nm after converting nitrate to nitrite. The nitrite concentration was calculated using a standard curve for sodium nitrite.…”

Section: Plant Materials and Preparation Of The Licorice Extractmentioning

confidence: 99%

Effects of the Licorice Extract against Tumor Growth and Cisplatin-Induced Toxicity in a Mouse Xenograft Model of Colon Cancer

Lee

Park

Lim

et al. 2007

Biological & Pharmaceutical Bulletin

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Cisplatin (cis-diamminedichloroplatinum II) is a platinum coordinated complex that is widely used as an antineoplastic agent for the treatment of many solid tumors, including cancers of the ovary, testis, lung, bladder, head and neck, cervix and endometrium.1) Despite its excellent anticancer activity, the clinical use of cisplatin is often limited by its undesirable side effects, such as severe nephrotoxicity and hepatotoxicity. 2,3) Although the precise mechanism for this cisplatin-induced toxicity is not well understood, cisplatin is taken up preferentially and accumulates in the human liver and kidney cells, 4) resulting in the enhanced production of reactive oxygen species (ROS) and the decrease in the antioxidant enzymes.5,6) Therefore, antioxidants have been administered before a cisplatin treatment to protect against nephrotoxicity. 7)Licorice is an esteemed crude drug in both the Orient and Occident that is originated from the dried roots of several Glycyrrhiza species, including Glycyrrhiza uralensis FISCHER, G. glabra LINNE and G. inflata BATALIN. 8,9) In Chinese traditional medicine, licorice remains one of the most commonly prescribed herbs and has been used in the treatment of various ailments ranging from tuberculosis to peptic ulcers.10) Licorice has also been employed as a flavoring and sweetening agent, as well as a demulcent and expectorant in Western countries.11) The chemical constituents of licorice include glycyrrhizin and its aglycone, glycyrrhetinic acid, which are originally isolated from aqueous extracts and are used in the treatment of hyperlipemia, atherosclerosis, viral diseases, allergic inflammation and hepatotoxicity.12,13) The acetone or ethanol extract of licorice has species-specific flavonoids, such as liquiritin, isoliquiritin and their corresponding aglycones, glabridin, glabrol, glabrene, hispaglabridin A and hispaglabridin B.14,15) These flavonoids exhibit antioxidative, 16) superoxide scavenging 16) and anticarcinogenic activities.17) However, in vivo antitumor activity of a licorice extract and its protective activity on cisplatin-induced toxicity have not yet been studied.In the present study to assess the antitumor activity of a licorice extract and whether it has the potential to serve as a beneficial supplement during cisplatin chemotherapy, we examined the inhibitory effect of the licorice extract alone and in combination with cisplatin on the tumor growth, and its protective effect against cisplatin-induced nephrotoxicity and hepatotoxicity in mice xenografted with mouse colon carcinoma cells. MATERIALS AND METHODSChemical Cisplatin, phenylmethylsulfonyl fluoride (PMSF), sodium nitrite, 1,1,3,3-tetramethoxypropane, reduced glutathione (GSH), 5,5Ј-dithiobis(2-nitrobenzoic acid) (DTNB), glutathione reductase, reduced nicotinamide adenine dinucleotide phosphate (NADPH), superoxide dismutase (SOD), xanthine oxidase, a-naphthylamine, sulfanilic acid, xanthine, catalase and 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole (purpald ® ) were purchased from SigmaAldrich Chem...

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“…1). The nitrate levels in plasma and the nitrite production are fairly stable from 30 min to at least 120 min after nitrate ingestion (8). Hence the nitrate level measured is a good estimation of the nitrate level in plasma during the acquisition of the ASL images.…”

Section: Blood Samplesmentioning

confidence: 83%

Dietary nitrate facilitates an acetazolamide-induced increase in cerebral blood flow during visual stimulation

Aamand

Dalsgaard

et al. 2014

Journal of Applied Physiology

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Aamand R, Ho YL, Dalsgaard T, Roepstorff A, Lund TE. Dietary nitrate facilitates an acetazolamide-induced increase in cerebral blood flow during visual stimulation. J Appl Physiol 116: 267-273, 2014. First published December 12, 2013 doi:10.1152/japplphysiol.00797.2013The carbonic anhydrase (CA) inhibitor acetazolamide (AZ) is used routinely to estimate cerebrovascular reserve capacity in patients, as it reliably increases cerebral blood flow (CBF). However, the mechanism by which AZ accomplishes this CBF increase is not entirely understood. We recently discovered that CA can produce nitric oxide (NO) from nitrite, and that AZ enhances this NO production in vitro. In fact, this interaction between AZ and CA accounted for a large part of AZ's vasodilatory action, which fits well with the known vasodilatory potency of NO. The present study aimed to assess whether AZ acts similarly in vivo in the human cerebrovascular system. Hence, we increased or minimized the dietary intake of nitrate in 20 healthy male participants, showed them a full-field flickering dartboard, and measured their CBF response to this visual stimulus with arterial spin labeling. Doing so, we found a significant positive interaction between the dietary intake of nitrate and the CBF modulation afforded by AZ during visual stimulation. In addition, but contrary to studies conducted in elderly participants, we report no effect of nitrate intake on resting CBF in healthy human participants. The present study provides in vivo support for an enhancing effect of AZ on the NO production from nitrite catalyzed by CA in the cerebrovascular system. Furthermore, our results, in combination with the results of other groups, indicate that nitrate may have significant importance to vascular function when the cerebrovascular system is challenged by age or disease.nitrate; cerebral blood flow; nitric oxide; acetazolamide ACETAZOLAMIDE (AZ) IS WELL known to increase cerebral blood flow (CBF) and is used routinely to estimate cerebrovascular reserve capacity (CVRC) in patients (13, 32). However, the mechanism by which AZ accomplishes this CBF increase is not entirely understood (35). AZ is an inhibitor of the ubiquitous enzyme carbonic anhydrase (CA), which normally catalyzes the reversible hydration of CO 2 (CO 2 ϩ H 2 O ↔ H 2 CO 3 ↔ HCO 3 Ϫ ϩ H ϩ ). CA is thus an integral part of the system that rids the body of the CO 2 produced in tissues (26). For the same reason, CA also acts to equilibrate the pH transients occurring, e.g., upon metabolic activity. The effect of AZ is usually assumed to be linked to cerebral acidosis caused by an AZ-induced increase in the cerebral partial pressure of CO 2 (PCO 2 ) (5).We recently discovered that CA is also capable of catalyzing the conversion of the endogenous anion nitrite into nitric oxide (NO) (2), a potent vasodilator. In that study, we also attempted to block CA's catalyzation of the NO production by introducing the CA inhibitor AZ to the reaction. However, to our surprise, AZ markedly increased the production of NO ...

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Pharmacokinetic Aspects of Inorganic Nitrate Ingestion in Man

Cited by 47 publications

References 14 publications

Reduced production of nitric oxide during haemodialysis

Reduced production of nitric oxide during haemodialysis

Effects of the Licorice Extract against Tumor Growth and Cisplatin-Induced Toxicity in a Mouse Xenograft Model of Colon Cancer

Dietary nitrate facilitates an acetazolamide-induced increase in cerebral blood flow during visual stimulation

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