Polycystin deficiency induces dopamine-reversible alterations in flow-mediated dilatation and vascular nitric oxide release in humans.

Autosomal dominant polycystic kidney disease (ADPKD) is a renal hereditary disorder associated with increased cardiovascular mortality, due to mutations in polycystin-1 and polycystin-2 genes. Endothelial polycystin-deficient cells have an altered mechanosensitivity to fluid shear stress and subsequent deficit in calcium-induced nitric oxide release, prevented by dopamine receptor stimulation. However, the impact of polycystin deficiency on endothelial function in ADPKD patients is still largely unknown. Here we assessed endothelium-dependent flow-mediated dilatation in 21 normotensive ADPKD patients and 21 healthy control subjects, during sustained (hand skin heating) and transient (postischemic hyperemia) flow stimulation. Flow-mediated dilatation was less marked in ADPKD patients than in controls during heating, but it was similar during postischemic hyperemia. There was no difference in endothelium-independent dilatation in response to glyceryl trinitrate. Local plasma nitrite, an indicator of nitric oxide availability, increased during heating in controls but not in patients. Brachial infusion of dopamine in a subset of ADPKD patients stimulated plasma nitrite increase during heating and improved flow-mediated dilatation. Thus, ADPKD patients display a loss of nitric oxide release and an associated reduction in endothelium-dependent dilatation of conduit arteries during sustained blood flow increase. The correction of these anomalies by dopamine suggests future therapeutic strategies that could reduce the occurrence of cardiovascular events in ADPKD.

Epoxyeicosatrienoic acids contribute with altered nitric oxide and endothelin-1 pathways to conduit artery endothelial dysfunction in essential hypertension.

BACKGROUND: We sought to clarify, using functional and biological approaches, the role of epoxyeicosatrienoic acids, nitric oxide (NO)/reactive oxygen species balance, and endothelin-1 in conduit artery endothelial dysfunction during essential hypertension. METHODS AND RESULTS: Radial artery diameter and mean wall shear stress were determined in 28 untreated patients with essential hypertension and 30 normotensive control subjects during endothelium-dependent flow-mediated dilatation induced by hand skin heating. The role of epoxyeicosatrienoic acids and NO was assessed with the brachial infusion of inhibitors of cytochrome P450 epoxygenases (fluconazole) and NO synthase (N(G)-monomethyl-l-arginine [L-NMMA]). Compared with controls, hypertensive patients exhibited a decreased flow-mediated dilatation in response to postischemic hyperemia as well as to heating, as shown by the lesser slope of their diameter-shear stress relationship. In controls, heating-induced flow-mediated dilatation was reduced by fluconazole, L-NMMA, and, to a larger extent, by L-NMMA+fluconazole. In patients, flow-mediated dilatation was not affected by fluconazole and was reduced by L-NMMA and L-NMMA+fluconazole to a lesser extent than in controls. Furthermore, local plasma epoxyeicosatrienoic acids increased during heating in controls (an effect diminished by fluconazole) but not in patients. Plasma nitrite, an indicator of NO availability, increased during heating in controls (an effect abolished by L-NMMA) and, to a lesser extent, in patients, whereas, inversely, reactive oxygen species increased more in patients (an effect diminished by L-NMMA). Plasma endothelin-1 decreased during heating in controls but not in patients. CONCLUSIONS: These results show that an impaired role of epoxyeicosatrienoic acids contributes, together with an alteration in NO/reactive oxygen species balance and endothelin-1 pathway, to conduit artery endothelial dysfunction in essential hypertension. CLINICAL TRIAL REGISTRATION: https://www.eudract.ema.europa.eu. Unique identifier: RCB2007-A001-10-53.

Soluble epoxide hydrolase inhibition improves myocardial perfusion and function in experimental heart failure.

The study addressed the hypothesis that soluble epoxide hydrolase (sEH) inhibition, which increases cardiovascular protective epoxyeicosatrienoic acids (EETs), exerts beneficial effects in an established chronic heart failure (CHF) model. In CHF rats, left ventricular (LV) function, perfusion and remodeling were assessed using MRI and invasive hemodynamics after 42-day (starting 8 days after coronary ligation) and delayed 3-day (starting 47 days after coronary ligation) treatments with the sEH inhibitor AUDA (twice 0.25 mg/day). Delayed 3-day and 42-day AUDA increased plasma EETs demonstrating the effective inhibition of sEH. Delayed 3-day and 42-day AUDA enhanced cardiac output without change in arterial pressure, thus reducing total peripheral resistance. Both treatment periods increased the slope of the LV end-systolic pressure-volume relation, but only 42-day AUDA decreased LV end-diastolic pressure, relaxation constant Tau and the slope of the LV end-diastolic pressure-volume relation, associated with a reduced LV diastolic volume and collagen density. Delayed 3-day and, to a larger extent, 42-day AUDA increased LV perfusion associated with a decreased LV hypoxia-inducible factor-1alpha. Both treatment periods decreased reactive oxygen species level and increased reduced-oxidized glutathione ratio. Finally, MSPPOH, an inhibitor of the EET-synthesizing enzyme cytochrome epoxygenases, abolished the beneficial effects of 3-day AUDA on LV function and perfusion. Augmentation of EET availability by pharmacological inhibition of sEH increases LV diastolic and systolic functions in established CHF. This notably results from short-term processes, i.e. increased LV perfusion, reduced LV oxidative stress and peripheral vasodilatation, but also from long-term effects, i.e. reduced LV remodeling.

Human cytochrome P450 4F3: structure, functions, and prospects.

Cytochrome P450 4F3 (CYP4F3), originally identified as one of the leukotriene B4 ω-hydroxylases, belongs to a CYP gene family that comprises several members, which participate in the metabolism of various endobiotics, as well as some xenobiotics. The CYP4F gene family is clustered in a 0.5-Mb stretch of genomic DNA on the p13 region of chromosome 19. Apart from the ω-hydroxylation of leukotriene B4 and prostaglandins, CYP4F3 is the main catalyst in the oxidation of fatty acid epoxides. CYP4F3 expression results from the synthesis of two distinct enzymes, CYP4F3A and CYP4F3B, which originate from the alternative splicing of a single pre-mRNA precursor molecule. Remarkably, the selection of either isoform is part of a tissue-specific control through which CYP3F3A is mostly expressed in leukocytes and CYP4F3B mostly in the liver. Recently, CYP4F3 single nucleotide polymorphisms have been incriminated in the onset of pathologies, including celiac or Crohn's diseases. Although much has been discovered in the regulation and function of CYP4F2, the closest CYP4F subfamily member, analyses of CYP4F3 enzymes lag somewhat behind in the field of our knowledge. In this short review, emphasis will be placed on the regulation and the functional roles of human CYP4F3.

ATF4 and the integrated stress response are induced by ethanol and cytochrome P450 2E1 in human hepatocytes.

BACKGROUND & AIMS: Molecular mechanisms underlying alcoholic liver disease (ALD) are still not fully understood. Activating transcription factor-4 (ATF4) is the master coordinator of the integrated stress response (ISR), an adaptive pathway triggered by multiple stressors. which can promote cell death and induce metabolic dysregulation if the stress is intense or prolonged. The aim of this study was to assess the effect of alcohol on the ISR signaling pathway in human liver cells and to define the role of cytochrome P450 2E1 (CYP2E1) in this response. METHODS: Primary cultured human hepatocytes and human HepG2 cells over-expressing CYP2E1 by adenoviral infection were exposed to ethanol (25-100mM) for 8-48h. RESULTS: Ethanol treatment of both liver cells up-regulated ATF4 as well as the pro-survival and the pro-apoptotic transcriptional program of the ISR. Indeed, in CYP2E1-expressing HepG2 cells exposed to ethanol, the expression of ISR target genes (HMOX-1, GCLC, AsnS, IGFBP-1, GADD34,CHOP, ATF3, CHAC1) was induced. Up-regulation of ATF4 and the ISR transcriptional program was decreased by addition of the anti-oxidant glutathione. Several mechanisms mediated ATF4 protein induction, including, at early times, the phosphorylation of eIF2α which controls ATF4 translation, and, at later times, increased mRNA level and increased stability of the protein. A decrease in cell survival was also observed. CONCLUSIONS: This study demonstrates that both CYP2E1 and ethanol induce ATF4 and the integrated stress response, a pathway which coordinates signals from multiple stresses, as well as established risk factors for ALD, and can display detrimental cellular effects upon prolonged activation.

Stereoselective epoxidation of the last double bond of polyunsaturated fatty acids by human cytochromes P450.

Cytochromes P450 (CYPs) metabolize polyunsaturated long-chain fatty acids (PUFA-LC) to several classes of oxygenated metabolites. Through use of human recombinant CYPs, we recently showed that CYP1A1, -2C19, -2D6, -2E1, and -3A4 are mainly hydroxylases, whereas CYP1A2, -2C8, -2C9, and -2J2 are mainly epoxygenases of arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), respectively. It is worth noting that the last double bond of these PUFAs, i.e., omega6 in AA or omega3 in EPA and DHA, respectively, was preferentially epoxidized. In this study, we have characterized the stereoselectivity of this epoxidation reaction by comparison with the PUFA-LC epoxide stereoisomers obtained from the enantioselective bacterial CYP102A1 F87V. The stereoselectivity of the epoxidation of the last olefin of AA (omega6), EPA (omega3), or DHA (omega3) differed between the CYP isoforms but was similar for EPA and DHA. These data give additional insight into the PUFA-LC epoxide enantiomers generated by the hepatic CYPs.

Metabolism of eicosapentaenoic and docosahexaenoic acids by recombinant human cytochromes P450.

Epoxidation and hydroxylation of arachidonic acid (AA) are both catalyzed by cytochromes P450s (CYPs). The oxidized metabolites are known to be involved in the regulation of vascular tone and renal function. By using a panel of 15 human recombinant CYPs, this study demonstrates that other polyunsaturated long-chain fatty acids (PUFA-LC), especially the omega3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are also epoxidised. The regioselectivity of epoxidation of four PUFA-LC by CYPs was investigated. Among the several CYPs tested, CYP2C9/2C19 and 1A2 were the most efficient in EPA and DHA epoxidations. It ensued that 10muM of these two omega3 fatty acids decreased by more than 80% and 60%, respectively, the formation by CYP2C9 of AA-epoxidised derivatives. These findings suggest that some physiological effects of omega3 fatty acids may be due to a shift in the generation of active epoxidised metabolites of AA through CYP-mediated catalysis.

Determination of epoxyeicosatrienoic acids in human red blood cells and plasma by GC/MS in the NICI mode.

Epoxyeicosatrienoic acids (EETs) are cytochrome P450 metabolites of arachidonic acid involved in the regulation of vascular tone. Despite the importance of EETs in a variety of physiological effects, few methods have been developed to quantify them in human blood. This led us to develop a method by GC/MS with negative ion chemical ionization. As EETs are primarily located in phospholipids, red blood cells (RBCs) and plasma phospholipids were hydrolyzed with phospholipase A(2) after a solid phase extraction. Then, EETs were derivatized as pentafluorobenzyl esters, and [(2)H(8)]-arachidonic acid was used as internal standard for quantification. EETs were found to be at concentrations of 106+/-37ng mL(-1) in plasma and 33.4+/-8.5 ng/10(9) RBCs (mean+/-S.D.) in 10 healthy volunteers. Their amount in RBCs was 3-fold that in plasma; both parameters proved to be well correlated.

Involvement of cytochrome P450 1A2 in the biotransformation of trans-resveratrol in human liver microsomes.

This study was aimed at identifying the isoform(s) of human liver cytochrome P450 (CYP) involved in the hepatic biotransformation of trans-resveratrol (trans-3,5,4'-trihydroxystilbene). Trans-resveratrol metabolism was found to yield two major metabolites, piceatannol (3,5,3',4'-tetrahydroxystilbene) and another tetrahydroxystilbene named M1. Trans-resveratrol was hydroxylated to give piceatannol and M1 with apparent K(m) of 21 and 31 microM, respectively. Metabolic rates were in the range 14-101 pmol min(-1) mg(-1) protein for piceatannol and 29-161 pmol min(-1) mg(-1) protein for M1 in the 13 human liver microsomes tested. Using microsomal preparations from different human liver samples, piceatannol and M1 formation significantly correlated with ethoxy-resorufin-O-deethylation (r(2) = 0.84 and 0.88, respectively), phenacetin-O-deethylation (r(2) = 0.92 and 0.94) and immuno-quantified CYP1A2 (r(2) = 0.85 and 0.90). Formation of these metabolites was markedly inhibited by alpha-naphthoflavone and furafylline, two inhibitors of CYP1A2. Antibodies raised against CYP1A2 also inhibited the biotransformation of trans-resveratrol. In addition, the metabolism of trans-resveratrol into these two metabolites was catalyzed by recombinant human CYP1A1, CYP1A2 and CYP1B1. Our results provide evidence that in human liver, CYP1A2 plays a major role in the metabolism of trans-resveratrol into piceatannol and tetrahydroxystilbene M1.

Differential inhibition of human cytochrome P450 enzymes by epsilon-viniferin, the dimer of resveratrol: comparison with resveratrol and polyphenols from alcoholized beverages.

epsilon-Viniferin, a dimer of resveratrol, was isolated in wine at concentration between 0.5 and 5 microM. As resveratrol and polyphenols from red wine were reported to inhibit cytochrome P450 (CYP) activities, this led us to investigate the inhibitory effects of epsilon-viniferin on human CYP1A1, CYP1A2, CYP1B1, CYP2A6, CYP2B6, CYP2E1, CYP3A4 and CYP4A activities. These effects were compared to those of resveratrol and non volatiles compounds from red wine or various Cognac(R) beverages (enriched with oak-polyphenols). Assays were carried out on human liver microsomes and heterologously expressed CYPs. Ethoxyresorufin, coumarin, benzoxyresorufin, chlorzoxazone, testosterone and lauric acid were used as selective substrates for CYP1A1, CYP1A2, CYP1B1, CYP2A6, CYP2B6, CYP2E1, CYP3A4 and CYP4A, respectively. epsilon-viniferin displayed a more potent inhibitory effect than resveratrol for all the CYP activities tested (Ki 0.5 to 20 microM vs. 10 to 100 microM, respectively). This effect was not due to an inhibition of the NADPH reductase. A particularly potent inhibitory effect was shown for CYP1A1, CYP1B1 and CYP2B6 which are involved in bioactivation of numerous carcinogens. epsilon-viniferin was not a mechanism-based inhibitor of human CYPs. It displayed, like resveratrol, mixed-type inhibitions for all the CYP tested, except for CYP2E1 (non-competitive). Comparison of the inhibitory effects exerted on CYP activities by epsilon-viniferin, resveratrol and non volatile components from red wine or various Cognac beverages showed that neither resveratrol, nor epsilon-viniferin is the main CYP inhibitor present in red wine solids.

Diversity of selective environmental substrates for human cytochrome P450 2A6: alkoxyethers, nicotine, coumarin, N-nitrosodiethylamine, and N-nitrosobenzylmethylamine.

Cytochrome P450 2A6 constitutes 5-10% of the total microsomal CYPs of human liver. Although CYP2A6 is the major coumarin 7-hydroxylase, other known substrates of CYP2A6 include many toxicants and precarcinogens. The chemical structure diversity of these substrates raises the question of their selectivity. Thus, kinetic parameters were determined for the hydroxylation of five substrates of diverse chemical structures known to be selective for cytochrome P450 2A6: methyl tert-butyl ether (MTBE), nicotine, coumarin, N-nitrosobenzylmethylamine (NBzMA), and N-nitrosodiethylamine (NDEA). Sources of enzymes were either human liver microsomes or heterologously expressed CYPs. Coumarin was shown to be the substrate with the highest affinity, followed by NDEA, nicotine, NBzMA, and MTBE. Variability of CYP2A6 catalytic activities in human liver was between 24-fold for MTBE to sevenfold for coumarin, while CYP2A6 content varied 68-fold in human liver microsomes. These five catalytic activities were highly significantly correlated between them and with hepatic CYP2A6 content. The most selective chemical inhibitor of these five substrates was shown to be 8-methoxypsoralen. Based upon chemical inhibition of the enzymatic activities of pure recombinant human CYPs, it cannot be totally excluded that P450s other than CYP2A6, especially CYP2E1, are involved, although to a lesser extent, in NDEA and NBzMA metabolism. In conclusion, the prototype probes for CYP2A6 phenotyping are coumarin and nicotine.

CYP2E1 regulation by benzene and other small organic chemicals in rat liver and peripheral lymphocytes.

The inducibility of CYP2E1 was investigated in liver and peripheral lymphocytes of rats treated with benzene (0-10 mmol/kg body weight (bw), daily for 3 days, i.p., or 0 and 5 mmol/kg bw, daily for 14 days, i.p.) or toluene (0 and 5 mmol/kg bw, daily for 3 days, i.p.) and compared with that of pyridine (5 mmol/kg bw, i.p.) or acetone (5% in drinking water) both daily for 3 days. Acute benzene treatment (5 mmol/kg bw) increased both CYP2E1 apo-protein (2-fold) and p-nitrophenol hydroxylase (p-NPH) activity (1.4-fold) in liver, and CYP2E1 mRNA in both liver (2.2-fold) and peripheral lymphocytes (2.9-fold). The response to toluene was qualitatively similar, although smaller than that to benzene. As expected, acetone and pyridine treatments resulted in a 2- to 3-fold increase of p-NPH activity and CYP2E1 apo-protein content in liver, but not the mRNA levels. In addition, acute benzene and acetone treatments increased the 6-hydroxychlorzoxazone/chlorzoxazone metabolic ratio 1.6- and 3.1-fold, respectively. The subchronic treatment with benzene increased CYP2E1 mRNA and apo-protein from days 2 and 3 to day 14, respectively, whereas the enzyme activity increased transiently on days 3 and 5 only. These results show that acute/subacute benzene and acute toluene treatments induce CYP2E1 expression probably through a similar mechanism which might be different from that of pyridine or acetone, in that the former increase mRNA levels, both in liver and in peripheral lymphocytes, whereas the latter stabilized the apo-protein.

[Pseudohypobicarbonatemia in a patient with a kappa IgA monoclonal gammapathy]. / Pseudohypobicarbonatémie chez une patiente atteinte d'une gammapathie monoclonale à IgA kappa.

Paraprotein interferences assays are known but rather unusual in clinical chemistry.we here report a paraprotein interference with a bicarbonate assay in a IgA kappa-type myeloma patient. Serum bicarbonate level was assessed by the enzymatic method of a multiparametric chemistry analyzer (Advia 1800, Siemens) as well as a specific electrode assay on a blood gas analyzer (GEM 4000, IL). Paraprotein interference with the enzymatic assay was evidenced by an abnomally low bicarbonate level measured by the enzymatic method in contrast with usual levels obtained by using the gas analyzer and with the clinical status of the patient. Therefore, gammapathy has to be taken into consideration when interpreting biological data.

Impaired role of epoxyeicosatrienoic acids in the regulation of basal conduit artery diameter during essential hypertension.

In young healthy subjects, epoxyeicosatrienoic acids synthesized by endothelial cytochrome P450 epoxygenases maintain basal conduit artery diameter during altered NO availability. Whether this compensatory mechanism is effective during essential hypertension is unknown. Radial artery diameter, blood flow, and mean wall shear stress were determined in 14 nontreated essential hypertensive patients and 14 normotensive control subjects during 8 minutes of brachial infusion for inhibitors of cytochrome P450 epoxygenases (fluconazole, 0.4 µmol/min) and NO synthase (N(G)-monomethyl-L-arginine, 8 µmol/min) alone and in combination. In controls, the radial artery diameter was reduced by fluconazole (-0.034 ± 0.012 mm) and N(G)-monomethyl-L-arginine (-0.037 ± 0.010 mm) and to a larger extent by their combination (-0.137 ± 0.011 mm), demonstrating a synergic effect. In contrast, the radial diameter in hypertensive patients was not affected by fluconazole (0.010 ± 0.014 mm) but was reduced by N(G)-monomethyl-L-arginine (-0.091 ± 0.008 mm) to a larger extent than in controls. In parallel, N(G)-monomethyl-L-arginine decreased local plasma nitrite to a lesser extent in hypertensive patients (-14 ± 5 nmol/L) than in controls (-50 ± 10 nmol/L). Moreover, the addition of fluconazole to N(G)-monomethyl-L-arginine did not further decrease radial diameter in patients (-0.086 ± 0.011 mm). Accordingly, fluconazole significantly decreased local epoxyeicosatrienoic acid plasma level in controls (-2.0 ± 0.6 ng/mL) but not in patients (-0.9 ± 0.4 ng/mL). Inhibitors effects on blood flow and endothelium-independent dilatation to sodium nitroprusside were similar between groups. These results show that, in contrast to normotensive subjects, epoxyeicosatrienoic acids did not contribute to the regulation of basal conduit artery diameter and did not compensate for altered NO availability to maintain this diameter in essential hypertensive patients.

Tecnologias inovadoras do cuidado em enfermagem / Innovative technologies of nursing care

Objetivo: refletir acerca da conceituação de tecnologia como campo do saber de enfermagem, bem como a produção de tecnologias na área. Metodologia: Trata-se de uma reflexão teórica. Resultados: Historicamente, a concepção de tecnologia é utilizada como um produto ou equipamento, entretanto, ela também compreende saberes para geração e utilização de produtos e organização das relações humanas. O saber de Enfermagem é constituído por técnicas e tecnologias produzidas em sua práxis, como: Tecnologias do Cuidado em Enfermagem e Tecnologias Educacionais. Conclusão: Contudo, emerge a necessidade de (re) discutir as relações entre tecnologias na enfermagem para contemplar o pensamento tecnológico em sua ambivalência.

Objective: to reflect about the conceptualization of technology as a field of knowledge in nursing, as well as the production of technologies in the area. Methodology: it is a theoretical reflection. Results: historically, the conception of technology is used as a productoran equipment, however, it also includes knowledge to generate and use products and organizate of human relations. The knowledge of Nursing consists of techniques and technologies produced in its praxis, as: Technologies of Nursing Care and Educational Technologies. Conclusion: however, there emerges the need to (re) to discuss the relations between technologies in nursing to contemplate the thought technology in its ambivalence.

Objetivo: reflexionar sobre la conceptualización de la tecnología como un campo del conocimiento en enfermería, así como la producción de tecnologías en el área. Metodología: se trata de una reflexión teórica. Resultados: históricamente, la concepción de la tecnología es utilizada como un producto o material, sin embargo, también incluye los conocimientos para la generación y uso de los productos y la organización de las relaciones humanas. El conocimiento de Enfermería consiste en técnicas y tecnologías producidas en su praxis, como: Tecnologías de los Cuidados de Enfermería y Tecnologías Educativas. Conclusión: sin embargo, surge la necesidad de (re) discutir las relaciones entre las tecnologías en la enfermería para contemplar el pensamiento tecnológico en su ambivalencia.

N-3 long chain polyunsaturated fatty acids: a nutritional tool to prevent insulin resistance associated to type 2 diabetes and obesity?

n-3 long chain polyunsaturated fatty acids (n-3 LC-PUFA), mainly eicosapentaenoic acid (EPA, 20:5 n-3) and docosahexaenoic acid (DHA, 22:6 n-3), are present in mammal tissues both from endogenous synthesis from desaturation and elongation of 18:3 n-3 and/or from dietary origin (marine products and fish oils). In rodents in vivo, n-3 LC-PUFA have a protective effect against high fat diet induced insulin resistance. Such an effect is explained at the molecular level by the prevention of many alterations of insulin signaling induced by a high fat diet. Indeed, the protective effect of n-3 LC-PUFA results from the following: (a) the prevention of the decrease of phosphatidyl inositol 3' kinase (PI3 kinase) activity and of the depletion of the glucose transporter protein GLUT4 in the muscle; (b) the prevention of the decreased expression of GLUT4 in adipose tissue. In addition, n-3 LC-PUFA inhibit both the activity and expression of liver glucose-6-phosphatase which could explain the protective effect with respect to the excessive hepatic glucose output induced by a high fat diet. n-3 LC-PUFA also decrease muscle intramyofibrillar triglycerides and liver steatosis. This last effect results on the one hand, from a decreased expression of lipogenesis enzymes and of delta 9 desaturase (via a depleting effect on sterol response element binding protein 1c (SREBP-1c). On the other hand, n-3 LC-PUFA stimulate fatty acid oxidation in the liver (via the activation of peroxisome proliferator activated receptor alpha (PPAR-alpha)). In patients with type 2 diabetes, fish oil dietary supplementation fails to reverse insulin resistance for unclear reasons, but systematically decreases plasma triglycerides. Conversely, in healthy humans, fish oil has many physiological effects. Indeed, fish oil reduces insulin response to oral glucose without altering the glycaemic response, abolishes extraggression at times of mental stress, decreases the activation of sympathetic activity during mental stress and also decreases plasma triglycerides. These effects are encouraging in the perspective of prevention of insulin resistance but further clinical and basic studies must be designed to confirm and complete our knowledge in this field.

"Loss of function" mutations in the cationic trypsinogen gene (PRSS1) may act as a protective factor against pancreatitis.

Several genetic factors have been well known to predispose one to chronic pancreatitis (CP). However, little is known about the genetic factors that may provide a protective effect against the disease. Having found a nonsense mutation (c.111C>A; Y37X) and a splicing mutation (IVS2+1G>A) in the cationic trypsinogen gene (protease, serine, 1; PRSS1) in alcoholics without the development of CP, but not in alcoholics with CP and patients with hereditary or idiopathic CP, we propose that while "gain of function" mutations in the PRSS1 gene predispose one to pancreatitis, "loss of function" mutations in the gene may protect one against the disease.