Changes in lens and erythrocyte glutathione reductase in response to exogenous flavin adenine dinucleotide and liver riboflavin content of rat on riboflavin deficient diet

Bhat, Krishna L.; Rao, P. Vasanth

doi:10.1016/s0271-5317(87)80046-5

Cited by 9 publications

(6 citation statements)

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“…BHAT suture, at the end of 50 days of feeding. Also, one (1.5%) riboflavin-deficient rat did develop mature cataract in both eyes.The lens wet weight and protein concentration of riboflavin-deficient and control rats were similar to those reported earlier [9]. Table 1 summarizes the differences in the activities of lens GSH-R, GSH-PX, G6PDH, activity coefficient of GSH-R, and the ratio of GSH-PX/GSH-R between riboflavin-deficient and control rats.…”

supporting

confidence: 79%

“…In conclusion, the results presented in this paper suggest that, though there exist conflicting reports in the literature about the role of riboflavin in cataract formation [1,[7][8][9]46], there are a host biochemical changes, including enhanced lipid peroxidation, lowered ascorbic acid levels, and CASH-activity and alterations in protein profiles in riboflavin deficiency [4], which are commonly associated with cataract. Therefore though riboflavin deficiency per se may not lead to frank cataracts, it is biochemically deleterious to lens metabolism and may lead to lens opacity in cases of prolonged deficiency.…”

Section: Pv Rao and Ks Bhat Discussionmentioning

confidence: 94%

“…FAD) of GSH-R was significantly decreased (p<0.001) in riboflavindeficient rat lenses, being 38 and 46% lower than values in pair-fed and ad libitum control groups lenses, respectively. While the enzyme activity assayed after the (in vitro) addition of FAD was not found to be significantly different among the three groups (data not given), it emerged that the activation coefficient of GSH-R, which is commonly used as an index of riboflavin nutritional status [9,10,21] was increased significantly (p<0.001) in riboflavin-deficient rats as compared with that of the controls. The activity of G6PDH was not significantly different among the 3 groups of rats studied.…”

Section: Methodsmentioning

confidence: 89%

“…Since, riboflavin deficiency often leads to reduced GSH-activity in various tissues including lens [7][8][9] and subsequent disturbances in the antioxidant system can lead to aggregation of lens proteins [5,6], in the present study an attempt has been made to unravel the possible significance of various defence systems against oxidant stress in riboflavin deficiency.…”

Section: Pv Ra® and Ks Bhatmentioning

confidence: 98%

“…The reaction was started by adding 0.12 ,u mol NADP+. GSH-R was assayed by the method of Bayoumi, and osalki [16] as described elsewhere [9]. Glutathioneperoxidase (GSH-PX) was assayed as described by Hochstein and Utley [17] with the following modification: The reaction mixture contained in 1 ml: 50 ,u mol phosphate buffer (pH 7.2), 2.5 ,u mol GSH, 0.5 ,u mol NaN3, 0.3 ,u mol EFTA, 0.1 ,u mol NADPH, 0.5 IU GSH-R, and 75 ,u 1 supernatant (enzyme preparation, 1 : 5 dilution).…”

mentioning

confidence: 99%

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Influence Dietary Riboflavin Deficiency on Lenticular Glutathione Redox Cycle, Lipid Peroxidation, and Free Radical Scavengers in the Rat

Rao

Bhat

1989

J. Clin. Biochem. Nutr.

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(first set of animals) or 0.05 M sodium phosphate buffer, pH 7.2 (second set of animals) using a Potter/Elvehj am glass homogenizer. A 7.5% homogenate was prepared from two lenses (third set of animals) in 5% ice-cold TCA. Aliquots of J. Clin. Biochem. Nutr. INFLUENCE OF RIBOFLAVINDEFICIENCY ON RAT LENS 197 the lens homogenate (Tris-EFTA buffer) were analysed for GSH and GSSG measured fluorimetrically [11] in a Hitachi 650-lOS spectrofluorimeter and for total and non-protein sulfhydryl groups with Ellman's reagent [12]. Lipid peroxide level was estimated (in terms of malondialdehyde (MICA)) in the phosphate buffer by the thiobarbituric acid (TBA) reaction [13] and ascorbic acid in 5,000>< g supernatant of 5% TCA homogenate, using orthophosphoric acid, ferric chloride and aa '-dipyridyl [14]. The remaining homogenate (Tris-EFTA buffer) was centrifuged at 20.000>< g in a Sorvall RCSB super-speed centrifuge at 4°C for 30 min. The 20,000>< g supernatant was used for the assay of glutathione redox cycle enzymes. Glucose 6-phosphate dehydrogenase (G6PDH) was assayed spectrophotometrically as described by Selvaraj, and Bhat [15]. The reaction mixture contained in 1.2 ml: 50,u mol glycylglycine buffer (pH 8.7), 12 ,u mol KCl, 12 ,u mol MgC12, 3 ,u mol nicotinamide, 61u mol glucose 6-phosphate, and 75 1a l lens tissue supernatant. The reaction was started by adding 0.12 ,u mol NADP+. GSH-R was assayed by the method of Bayoumi, and osalki [16] as described elsewhere [9]. Glutathioneperoxidase (GSH-PX) was assayed as described by Hochstein and Utley [17] with the following modification: The reaction mixture contained in 1 ml: 50 ,u mol phosphate buffer (pH 7.2), 2.5 ,u mol GSH, 0.5 ,u mol NaN3, 0.3 ,u mol EFTA, 0.1 ,u mol NADPH, 0.5 IU GSH-R, and 75 ,u 1 supernatant (enzyme preparation, 1 : 5 dilution). The reaction mixture was incubated at 37°C for 10 min and the reaction started by the addition of 0.251a mol tert-butyl hydroperoxide. Catalase in the 750 X g supernatant fraction of the homogenate prepared in phosphate buffer was assayed polarographically as described by Goldstein [18] with a polarograph (YSI, Model 5301) equipped with an oxygen monitor (model 53) and a recorder (LKB 2210). The activity of superoxide dismutase (SOIL) in supernatant fractions of the lens homogenate (phosphate buffer) obtained by centrifugation at 35,000>< g and 0-4°C for 25 min was determined spectrophotometrically by measuring the inhibition of autooxidation of pyrogallol [19]. Protein concentration was measured by the method of Lowry et al. [20]. Statistical analysis. The data was analysed by one way analysis of variance. The mean differences were also further tested by Duncan's multiple range test. RESULTSThis study spans three different animal experiments in every one of which riboflavin-deficient rats showed a severe growth retardation, hair loss, and skin lesions, all of which are characteristic features of riboflavin deficiency.Ocular examination revealed severe corneal vascularization in riboflavindeficient rats (30%) as comp...

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confidence: 79%