| Abstract: |
Ghrelin is a recently discovered hormone that has been shown to stimulate growth hormone (GH) release via activation of the GH secretogogue receptor, GHS-R1a. Ghrelin is predominantly produced by X/A-like cells of the stomach submucosa. Also, it was identified in other portions of the gastrointestinal tract, in salivary glands, lung, heart, liver, pancreas and other organs. It stimulates appetite, increases plasma free fatty acids, improves mild insulin resistance and suppresses insulin secretion.Aim: This study was designed to evaluate plasma Ghrelin levels in lean (control), streptozotocin-induced diabetic and HFD-fed rats and to found the association between exercise training and these Ghrelin levels.Materials and Methods: The study was done by using 72 adult male albino rats divided into 3 main groups: group I (control), group II (STZ- diabetic) and group III (HFD). Each group was further subdivided into3 subgroups: sedentary, moderate and exhaustive swimming exercise training.Results: In control: there was significant increase in plasma Ghrelin levels with exercise in an intensity dependent manner and this increase is due to affection of insulin level and BMI.In HFD group, there was significant reduction in plasma Ghrelin levels in none exercised rats. But, the levels increase with exercise. So, exercise affect Ghrelin level by alteration of insulin level and sensitivity and BMI.In STZ-Induced diabetic group, there was increase in plasma Ghrelin levels in none exercised rats. But, exercise stimulates insulin secretion in this group.Conclusion: -Exercise has regulatory effect on circulating Ghrelin levels.-Exercise increase Ghrelin levels in an intensity dependent manner.-Regulation of circulating Ghrelin levels by exercise occurs by multiple mechanisms according to the metabolic conditions:In control and STZ-diabetic groups the regulation is mainly by BMI. In HFD group: the regulation by insulin levels and BMIKey words: Ghrelin, GH secretogogue receptors..
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