Sma nitrate/nitrite levels differ significantly between these two groups at
Sma nitrate/nitrite levels differ significantly between these two groups at all the time point (P < 0.05) throughout the experiment after drug administration, and also between vitamin C and GSNO-treated dogs, and captopril treated-treated dogs (P < 0.05). Plasma nitrate/nitrite concentration also differ significantly betweenPage 5 of(page number not for citation purposes)BMC Pharmacology 2002,http://www.biomedcentral.com/1471-2210/2/3ODVPD 1LWUDWH1LWULWH RQFHQWUDWLRQ mPROcaptopril or control administered with water thereby prolonging postprandial hyperglycemia. As evident by comparisons of the area circumscribed by the plasma insulin response curve, the quantity of insulin released by the pancreas was significantly affected by the co-administration of vitamin C with the NO-donors, suggesting that inadequate insulin was secreted to dispose of the glucose load in the vitamin C and GSNO, or vitamin C and SNAPtreated dogs. The blood glucose values for the vitamin C and GSNO or vitamin C and SNAP-treated dogs were well outside of the normal limits at the 2.0-h and 2.5-h time points, and significantly elevated above their counterparts treated with only GSNO or SNAP (P < 0.05) whose values were also outside the normal range, suggesting further deterioration of glucose tolerance. PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/26795252 Nitric oxide is toxic at high physiological concentration where it appears to function as a cellular effector molecule that mediates both cytostatic and cytotoxic effect [16]. Previous evidence have indicated that pancreatic islet cells exposed to the NO-donor streptozotocin caused lasting, damage to the beta-cells, characterized by a persistent impairment in glucose metabolism and a defective insulin response [17], and that the NO-donor sodium nitroprusside caused lysis of islet cells in a concentration- and timedependent manner. The mechanism by which these drugs affect the pancreas could account for the hyperglycemic effect observed in the dogs treated with GSNO and SNAP. Vitamin C, an important determinant of the intracellular redox state, has been known to accelerate the decomposition of GSNO and SNAP increasing the release and availability of NO. The modulation of the bioactivity of GSNO by ascorbic acid is dependent on the presence of transition metal ions [18]. Reduced transition metal ions such as Cu+ catalyze the decomposition of GSNO and SNAP than do their oxidized forms eg, Cu2+[18]. Elevated levels of plasma nitrate/nitrite levels, assessed as NO production, was observed in vitamin C and GSNO or vitamin C and SNAP-treated dogs indicating enhanced NO release. The prolonged and exacerbated hyperglycemic effect could be explained in terms of the fact that exposure of the betacells to increased NO levels resulting in further deterioration in beta-cell function characterized by impairment in glucose metabolism and defective insulin response [17]. The enhanced NO released caused marked reduction in PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/25432023 the plasma insulin levels which are in agreement with previous observations which AZD-8055 site suggest that NO acts as a negative modulator of glucose stimulated insulin secretion, thus accounting for the pronounced hyperglycemic effect [19]. The solvent water was administered to the control dogs. Water was used because it can be considered as an “inactive treatment” with no capacity to enhance the generation of NO from its donors or possessing any antioxidant7LPH KFigure 7 Line graphs showing the effect of 20 mg/kg captopril (), 10 mg/kg of S-nitroso-N-acetylpenicillamine ( ), 1.