Effect of Glucocorticoids on Serum Level of Omentin-1 and The Possible Link with Insulin Resistance in Rats
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- Category: Vol. 85, June 2017
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Effect of Glucocorticoids on Serum Level of Omentin-1 and The Possible Link with Insulin Resistance in Rats, KHALED A.A. ABUL-FADLE
Abstract
Background: Omentin-1 is an adipokine that decreases insulin resistance and its level is affected by body weight and serum adiponectin level changes, while, glucocorticoids are steroid hormones, secreted by adrenal cortex, affect insulin resistance, body weight and serum level of adiponectin.
Objective: This study was designed to investigate the possible effect of glucocorticoids on serum level of omentin-1 in male albino rats and the possible link with insulin resis-tance.
Design: 30 adult male albino rats, weighting 170-190gm, were divided into three groups; control, dexamethasone treated (Hyper-C) and metyrapone treated (Hypo-C). In (Hyper-C) group, rats were injected with dexamethasone (1mg/kg/day intra peritoneal) for two weeks. In (Hypo-C) group, metyrapone was administered orally (by gavage) dissolved in saline (200mg/kg body weight) for two weeks. In the control group, normal saline was injected intraperitoneally (1ml/rat/day) for two weeks. Rats were kept fasting for 8 hours and then, sacrificed under ether anesthesia by decapitation. Serum levels of omentin-1, corticosterone, ACTH, glucose and insulin were measured. Insulin Resistance (IR) was estimated by calculation of the Homeostasis Model Assessment-IR (HOMA-IR) index. Body Mass Index (BMI) for rats in the different groups was calculated just before being sacrificed.
Results: There was a significant increase in BMI in Hyper-C group (p<0.001) in comparison to that of the control group, but, there was a significant decrease (p<0.001) in its value in Hypo-C group in comparison to that of the Hyper-C group. On the other hand, there was a significant increase in serum levels of both glucose (p<0.001) and insulin (p<0.001) in Hyper-C group in comparison to that in the control group. On the contrary, there was a significant decrease in serum levels of both glucose (p<0.001) and insulin (p<0.001) in Hypo-C group in comparison to that in the Hyper-C group. Moreover, there was a significant decrease in HOMA-IR (p<0.001) in the Hypo-C group in comparison to that in the Hyper-C group. Furthermore, there was a significant decrease in serum omen-tin-1 level in Hyper-C group (p<0.001) in comparison to that in the control group, but, there was a significant increase in its serum level in Hypo-C group (p<0.001) in comparison to that in the Hyper-C group. On other hand, there were insignificant negative correlations in the Hyper-C group between serum omentin-1 and serum level of both insulin (r=–0.6, p> 0.05) and corticosterone (r=–0.22, p-value p>0.05), respec-tively.
Conclusion: The results of this study demonstrated that changes in serum levels of omentin-1 could be a possible mechanism by which glucocorticoids affect insulin resistance.