Formation of DNA-protein crosslinks in intestine of rats treated with a single oral dose of NaNO₂.

<p>Formation of DNA-protein crosslinks in intestine of rats treated with a single oral dose of NaNO₂.</p

Effect of NaNO₂ on the activities of major antioxidant defense enzymes in rat intestinal homogenates.

<p>Effect of NaNO₂ on the activities of major antioxidant defense enzymes in rat intestinal homogenates.</p

Effect of NaNO₂ on the activities of BBM marker enzymes in isolated rat intestinal BBM vesicles.

<p>Effect of NaNO₂ on the activities of BBM marker enzymes in isolated rat intestinal BBM vesicles.</p

Effect of NaNO₂ on the activities of carbohydrate metabolic enzymes in rat intestinal homogenates.

<p>Effect of NaNO₂ on the activities of carbohydrate metabolic enzymes in rat intestinal homogenates.</p

Effect of NaNO₂ on antioxidant power of rat intestinal homogenates.

<p>Effect of NaNO₂ on antioxidant power of rat intestinal homogenates.</p

Kinetic studies with different enzymes in intestinal BBM vesicles.

<p>(A) Leucine aminopeptidase (LAP) (B) γ-glutamyl transferase (GGT) (C) alkaline phosphatase (ALP) and (D) sucrase. Enzyme activities were assayed at different substrate concentrations in samples from control, 20 mg, 40 mg, 60 mg and 75 mg/kg body weight NaNO₂ treated groups. Data were analysed by double reciprocal 1/v vs 1/[S] Lineweaver-Burk plots. Results are mean ± standard error of six different BBM preparations.</p

Effect of NaNO₂ on the activities of BBM marker enzymes in rat intestinal homogenates.

<p>Effect of NaNO₂ on the activities of BBM marker enzymes in rat intestinal homogenates.</p

Comet assay.

<p>DNA damage in intestinal mucosal cells was studied by the comet assay as described in Materials and Methods. (A) DNA of cells were visualized under a fluorescent microscope and 25 comets scored per slide. Control; 20 mg/kg body weight NaNO₂, I; 40 mg/kg body weight NaNO₂, II; 60 mg/kg body weight NaNO₂, III; 75 mg/kg body weight NaNO₂, IV. (B) Comet tail lengths were recorded using the image analysis system, Komet 5.5, Kinetic Imaging, Liverpool, UK. Results are mean ± standard error of six different samples. ^*Significantly different at p< 0.05 from control.</p

Agarose gel electrophoresis of DNA.

<p>The isolated DNA was electrophoresed on 0.7% agarose gels. Lane 1, control group; lane 2, 40 mg/kg body weight NaNO₂; lane 3, 60 mg/kg body weight NaNO₂; lane 4, 75 mg/kg body weight NaNO₂.</p

Effect of NaNO₂ on the activities of enzymes of rat intestinal BBM vesicles, under <i>in vitro</i> condition.

<p>Intestinal BBM vesicles (1 mg protein/ml in 50 mM sodium maleate buffer, pH 6.0), from control animals were incubated with varying concentrations (0–2.0 mM) of NaNO₂ at 37°C in a total reaction volume of 1.0 ml. At different time intervals after the addition of NaNO₂, aliquots were removed from the reaction mixture and assayed for enzyme activity. Results are expressed relative to enzyme activity in untreated BBM vesicle samples kept on ice which served as the control. Results of a typical experiment are shown here. (A) Leucine aminopeptidase (LAP) (B) γ-glutamyl transferase (GGT) (C) alkaline phosphatase (ALP) (D) sucrase.</p