تأثیر تزریق وریدی گرلین بر میانگین غلظت پلاسمایی انسولین در شترهای نابالغ تغذیه شده با سطوح مختلف انرژی
محورهای موضوعی :
آسیب شناسی درمانگاهی دامپزشکی
تاریخ دریافت : 1388/07/06
تاریخ پذیرش : 1389/02/22
تاریخ انتشار : 1388/09/01
کلید واژه:
گرلین,
هورمون انسولین,
شتر نابالغ,
چکیده مقاله :
چکیده
گرلین یک هورمون پپتیدی مترشحه از معده به گردش خون می باشد که توسط بافت های دیگر بدن مثل مغز وپانکراس نیز ساخته می شود. این پپتید به دلیل ترشح از بافت های مختلف دارای اثرات مختلف پاراکرینی و آندوکرینی می باشد که برخی از این اثرات شامل: تحریک ترشح هورمون هایACTH وGH ، افزایش اشتها ومتابولیسم کربوهیدرات ها می باشد. همچنین گرلین یک لیگاند طبیعی برای رسپتور محرک هورمون رشد (GHS-R) می باشد. گرلین وmRNA آن مانند رسپتور هورمون محرک رشد در پانکراس وسلول های جزایر بیان شده و متابولیسم گلوکز و ترشح انسولین را تنظیم می کند. از آنجا که تاکنون آزمایشات مبنی بر اثر گرلین بر ترشح انسولین در حیوانات شبه نشخوارکننده در مرحله قبل از بلوغ انجام نشده است، بنابراین هدف از انجام این تحقیق بررسی اثر گرلین بر ترشح انسولین درشترهای نابالغ بود. در این تحقیق 12 شتر به طور تصادفی به دو گروه مساوی تقسیم شدند. حیوانات در گروه 1 به مدت دو هفته با رژیم غذایی 100% انرژی و حیوانات گروه 2 به مدت دو هفته در رژیم غذایی 50% انرژی تغذیه شدند. بعد از دو هفته، شترهای هر گروه g/BWµ 8 گرلین به مدت چهار روز از طریق ورید وداج دریافت کردند. نمونه های خونی از تمام حیوانات قبل، همزمان (30 دقیقه بعد از تزریق گرلین) و بعد از مداخله طی چهار روز متوالی در هر مرحله از ورید وداج جمع آوری گردید و پلاسماهای خون، جهت تعیین غلظت انسولین به وسیله روش رادیو ایمنو اسی (RIA) مورد سنجش قرار گرفتند. داده ها وسط آزمون آنالیز واریانس یک طرفه با مقادیر تکراری و آزمون تعقیبی تی وابسته تجزیه و تحلیل شدند. مقادیر 05/0>p معنی دار تلقی شد. نتایج این تحقیق نشان داد که گرلین اثر کاهشی معنی داری بر میانگین غلظت پلاسمایی انسولین در شترهای نابالغ در رژیم های غذایی حاوی 100% و50% انرژی دارد و این اثر کاهشی در بین دو رژیم غذایی، اختلاف معنی داری باهم ندارد.
چکیده انگلیسی:
Abstract
Ghrelin is a peptide hormone secreted into the circulation from the stomach, but this peptide is also synthetized in a number of different body tissues including the brain and pancreas, suggesting both endocrine and paracrine effects. These include: stimulation of GH and ACTH secretion, an increase in appetite and diabetogenic effect on carbohydrate metabolism. Furthermore, ghrelin is the natural ligand of the growth hormone secretagogue receptor (GHS-R). Ghrelin and its mRNAas well as GH secretagogue receptor mRNAs are expressed in the pancreas and islet cells and regulates insulin release and glucose metabolism, but because the effect of ghrelin on insulin secretion before puberty in semiruminant animals has never been examined, therefore the purpose of the present research was to determine the effect of ghrelin on insulin secretion before puberty in camels. In this investigation 12 camels were randomly divided into two groups. Animals in each group were fed either 50% and 100% energy content in diet for 2 weeks. After 2 weeks camels received 8 μg ghrelin/kg body weight via their jugular vein for 4 days. Blood samples were collected from the jugular vein of all animals before, during (30 minutes after injection of ghrelin) and after the intervention for 4 continuous days and plasma insulin concentrations determined by RIA. Data obtained were analyzed by repeated measures –ANOVA and paired t-Test. p<0.05 were considered statistically significant. The results of this experiment indicated that the injection of ghrelin significantly decreased the mean plasma concentrations of insulin in pre pubertal camels receiving 50% and 100% dietary energy and there was no significant difference between the two diets regarling this effect.
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