Insulin decreases circulating vitamin E levels in humans

Galvan, Alfredo Quiñones; Muscelli, Elza; Catalano, Carlo; Natali, Andrea; Sanna, Giovanna; Masoni, A; Bernardini, B.; Barsacchi, Renata; Ferrannini, Ele

doi:10.1016/s0026-0495(96)90270-x

Cited by 29 publications

(14 citation statements)

References 34 publications

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“…This result is consistent with previous studies that have demonstrated a signifi cant relationship between the degree of insulin resistance and LDL oxidation [2,3] . With respect to the association between insulin resistance and plasma antioxidant vitamins, we found that the negative relationship between ␤ -carotene or ␥ -tocopherol and HOMA-IR, and between ␤ -carotene and urinary PGF 2 ␣ excretion, supports the results of Galvan et al [23] which demonstrated that physiological hyperinsulinemia is associated with decreased plasma levels of vitamin E. Furthermore, the highest tertile of the HOMA-IR group showed lower ␤ -carotene concentrations along with higher urinary PGF 2 ␣ excretion than the lowest tertile of the HOMA-IR group.…”

Section: Discussionsupporting

confidence: 89%

Relationship between Insulin Resistance and Lipid Peroxidation and Antioxidant Vitamins in Hypercholesterolemic Patients

et al. 2006

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Background: Several studies have reported that insulin resistance and compensatory hyperinsulinemia increased lipid peroxidation, suggesting the linking to each other. We investigated the relationships between insulin resistance index HOMA-IR and lipid peroxidation, plasma antioxidant status in non-diabetic, hypercholesterolemic patients. Methods: We measured the urinary excretion of 8-epi-prostaglandin F₂_α(PGF₂_α) levels as a measure of lipid peroxidation in vivo, total radical trapping antioxidant potential (TRAP) and fat-soluble antioxidant vitamins in 76 non-diabetic subjects with hypercholesterolemia (mean age 59 years, 25 males and 51 females). Insulin resistance was evaluated by homeostasis model assessment (HOMA-IR) derived from fasting glucose and insulin concentrations. Results: HOMA-IR was positively correlated with the urinary excretion of PGF₂_α (r = 0.222, p < 0.05) and negatively correlated with the TRAP (r = –0.211, p < 0.05) in total subjects. Furthermore, there were significant inverse relationships between HOMA-IR and lipid corrected fat-soluble vitamins such as β-carotene (r = –0.297, p < 0.01) and γ-tocopherol (r = –0.243, p < 0.05) and also significant inverse relation was found between lipid corrected β-carotene and the urinary PGF₂_αexcretion (r = –0.205, p < 0.05). When total subjects were divided into three groups according to tertiles of HOMA-IR, significant differences in urinary PGF₂_αexcretion (p < 0.05) and lipid corrected β-carotene (p < 0.005) among the three groups were observed. The highest HOMA-IR group had the higher levels of urinary PGF₂_αexcretion and lower levels of plasma β-carotene compared with the lowest HOMA-IR group. Conclusion: Our data showed that the insulin resistance of hypercholesterolemic patients increased oxidative stress and negatively influenced plasma antioxidant system. These results provide evidence in understanding mechanism linking insulin resistance and oxidative stress accompanied by reduced antioxidant system.

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Section: Discussionsupporting

confidence: 89%

Relationship between Insulin Resistance and Lipid Peroxidation and Antioxidant Vitamins in Hypercholesterolemic Patients

et al. 2006

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“…In accordance with our results, Carantani et al (1998) observed a significant relationship between insulin resistance and oxi-LDL in a group of nondiabetic patients (Carantoni et al, 1998). Glyan et al (1996) have recently raised the possibility of a pro-oxidant action of insulin in vivo by demonstrating a consistent free radical-scavenger molecule, during philological hyperinsulinemia (Galvan et al, 1996).…”

Section: Resultssupporting

confidence: 92%

Relationship among sera lipoprotein abnormalities in healthy individuals with background of diabetic sibling

Akbarzadeh¹,

Nabipour²,

Jaffari³

et al. 2013

Afr. J. Biotechnol.

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As the prevalence of lipoprotein abnormalities in adolescents is increasing dramatically, the identification of relevant risk factors is a major public health challenge. The aim of this study was to investigate whether a family history of diabetes could be a risk factor for lipid abnormalities in healthy individuals. This study is a cross-sectional case control study. 179 men and women were studied in two equal-member groups (with diabetic parents' background and without any diabetic sibling). Both groups matched in body mass index (BMI), age and sex. The serum concentration of oxidized-low density lipoprotein (LDL), Apo B100 and insulin were measured by enzyme linked immunosorbant assay technique and TG, Chol, HDL-C, FBS and GTT by enzymatic methods. The LDL-C level was calculated using the Friedewald formula. The results show that there were no significant variation in the amount of plasma FBS, GTT, Cho, TG, LDL and HDL between the two groups, whereas a significant increase was found in the amount of insulin (P = 0.02), Apo B100 (P = 0.001), OX-LDL (P = 0.001) and HOMA-IR (P = 0.03) in the case group as compared to the control group. We conclude that a family history of diabetic parents can lead to lipid parameters abnormalities and CVD risk factor via aggregation of inherited defected genes.

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“…An increase in the generation of ROS by peripheral blood leucocytes in response to acute hyperglycemia has been previously demonstrated in PCOS patients (11), and the finding that physiological and pharmacological insulin infusions in vivo or in vitro revealed the oxidative effect of insulin (32,33,34,35,36) raised the hypothesis of systemic redox impairment in such patients.…”

Section: Discussionmentioning

confidence: 88%

Inositol administration reduces oxidative stress in erythrocytes of patients with polycystic ovary syndrome

Donà¹,

Sabbadin²,

Fiore³

et al. 2012

European Journal of Endocrinology

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Objective: Possibly due to a deficiency of insulin mediators, polycystic ovary syndrome (PCOS) is often associated with insulin resistance (IR) and hyperinsulinemia, likely responsible for an elevated production of reactive oxygen species. We investigated oxidative-related alterations in erythrocytes and anti-inflammatory effects of inositol in women with PCOS before and after treatment with myo-inositol (MYO). Methods: Twenty-six normal-weight PCOS patients were investigated before and after MYO administration (1200 mg/day for 12 weeks; nZ18) or placebo (nZ8) by evaluating serum testosterone, serum androstenedione, fasting serum insulin, fasting serum glucose, insulin area under the curve (AUC), and glucose AUC after oral glucose tolerance test and homeostasis model of assessment-IR. In erythrocytes, band 3 tyrosine phosphorylation (Tyr-P) level, glutathione (GSH) content, and glutathionylated proteins (GSSP) were also assessed. Results: Data show that PCOS patients' erythrocytes underwent oxidative stress as indicated by band 3 Tyr-P values, reduced cytosolic GSH content, and increased membrane protein glutathionylation. MYO treatment significantly improved metabolic and biochemical parameters. Significant reductions were found in IR and serum values of androstenedione and testosterone. A significant association between band 3 Tyr-P levels and insulin AUC was found at baseline but disappeared after MYO treatment, while a correlation between band 3 Tyr-P and testosterone levels was detected both before and after MYO treatment. Conclusions: PCOS patients suffer from a systemic inflammatory status that induces erythrocyte membrane alterations. Treatment with MYO is effective in reducing hormonal, metabolic, and oxidative abnormalities in PCOS patients by improving IR.

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Insulin decreases circulating vitamin E levels in humans

Cited by 29 publications

References 34 publications

Relationship between Insulin Resistance and Lipid Peroxidation and Antioxidant Vitamins in Hypercholesterolemic Patients

Relationship between Insulin Resistance and Lipid Peroxidation and Antioxidant Vitamins in Hypercholesterolemic Patients

Relationship among sera lipoprotein abnormalities in healthy individuals with background of diabetic sibling

Inositol administration reduces oxidative stress in erythrocytes of patients with polycystic ovary syndrome

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