Increased glutathione conjugate transport: a possible compensatory protection mechanism against oxidative stress in obesity?

Abstract

Objective: To compare glutathione S-conjugate transport in obese and nonobese persons, and how glutathione S-conjugates are involved in the antioxidant status in obesity. Materials and methods: The efflux of glutathione conjugates and malondialdehyde (MDA) levels were measured in erythrocytes of obese (N ¼ 33) and nonobese (N ¼ 28) persons at every 30 min during a 120 min incubation time in vitro. 2,4-dinitrophenyl-S-glutathione (DNP-SG) represented the glutathione S-conjugate. Results: The efflux of conjugate in erythrocytes from obese subjects (7087147 DNP-SG efflux nmol/ml erythrocytes/h) was significantly higher than that of control group (4907105 DNP-SG efflux nmol/ml erythrocytes/h) (Po0.05). At all time points measured (30-120 min), there was an increase in DNP-SG efflux in obese group (Po0.05). This is manifested by a decrease in cellular DNP-SG levels. The susceptibility of erythrocytes to in vitro 1-chloro-2,4-dinitrobenzene (CDNB)-induced oxidative stress were greater for cells of control group (Po0.05), although hemolysis sensitivity of these cells are not different between both groups (P40.05). Following CDNB pretreatment, incubation of erythrocyte with vanadate, a DNP-SG transport inhibitor, resulted in an increase of MDA in both groups. However, in this case, the difference in susceptibility was not related to obesity. On the other hand, while erythrocyte glutathione level was lower in obese subjects (79% of control) than in controls (Po0.05), the adenosine 5 0 -triphosphate (ATP) levels, the enzyme activities of glutathione S-transferase (GST) and the conjugation capacities of the erythrocytes were not different between groups (P40.05). Conclusion: Obesity may increase erythrocyte glutathione conjugate transport independent from ATP and GST activity that may protect against MDA formation in vitro.

Antioxidant‐rich coffee reduces DNA damage, elevates glutathione status and contributes to weight control: Results from an intervention study

“…Thus, tGSH levels were inversely correlated to BMI values (linear regression analysis: R 5 À0.448). This is in line with previous reports on lower erythrocyte glutathione levels in obese subjects, compared to non-obese controls [14] and with an inverse correlation between GSH levels and body weight/BMI [15].…”

Obesity significantly alters the human sperm proteome, with potential implications for fertility

“…The loss of antioxidant capacity is another hallmark of obesity [57]. The tripeptide thiol antioxidant glutathione has been found at reduced levels in serum and various body tissues of obese individuals [58][59][60]. Of note, low glutathione levels have also been observed in the semen of men with various infertility diagnoses [61,62].…”

Plasma Protein Carbonyl and Thiol Stress Before and After Laparoscopic Gastric Banding in Morbidly Obese Patients

“…In the erythrocyte, major thiol GSH is the important reducing agent and antioxidant, and is involved in maintaining the cellular oxidation-reduction balance, and has been shown to protect cells from a wide variety of endogenous and exogenous insult. Ozaydin et al 22 reported that the erythrocyte GSH level was lower in obese subjects than in controls, and erythrocyte GSH-conjugate transport may increase in obesity-induced oxidative stress. Plasma metabolic parameters were also signif- icantly correlated with oxidative and antioxidant markers in this study.…”