This study aims to clarify the effects of exercise on levels of appetite regulatory hormones in plasma and hypothalamus of obese rats. Diet-induced obese rats undergo short- (40 min) and long-term (40 min, 5 days/week for 8 weeks) exercises. The rats ran at a speed of 20 m/min on a 5 degrees slope treadmill. Rats undergoing short-term exercise were divided into C, E0, E1, E3, E12, and E24. Rats undergoing long-term exercise (LE) were compared to long-term control (LC). Concentrations of ghrelin, obestatin, and neuropeptide Y (NPY) were measured using radio immuno-assay. Expression of ghrelin receptor (GHSR-1a), putative obestatin receptor (GPR-39), and NPY in the hypothalamus was measured by quantitative RT-PCR. After short-term exercise, the plasma concentrations of ghrelin and obestatin were not changed, but NPY decreased. Ghrelin and obestatin in the hypothalamus decreased, and recovered 12 until 24 h. NPY increased and recovered after 24 h. Expression of GHSR-1a and NPY was not changed and GPR-39 was not observed. In LE, these changes are different in plasma and hypothalamus. It would be concluded appetite and body weight of obese rats are decreased by exercise through reduced level of ghrelin in the hypothalamus. Obestatin seems to have no effect in exercise-induced change in appetite.
"It should be noted that information concerning the effect of exercise training on skeletal muscle, particularly soleus muscle ghrelin concentrations , is lacking. However, in a study by Wang et al , a short-(acute) and long-term (8 weeks) treadmill exercise training regimen (20 m/min, 5 degrees of grade, and 40 minutes per session) reduced hypothalamic total ghrelin and obestatin in rats. In the present study, the level of total ghrelin was significantly lower in trained rat soleus muscle at the end of the 6-week treadmill exercise program (25 m/min, 60 minutes per session). "
[Show abstract][Hide abstract] ABSTRACT: Ghrelin and agouti-related protein (AgRP) are orexigenic peptides secreted from stomach mucosa and the arcuate nucleus of the hypothalamus, respectively. Both peptides affect feeding behavior and play a role in energy balance, glucose homeostasis, and adiposity. The purpose of the current study was to determine the effects of moderate-term (6 weeks) running regimen on resting levels of ghrelin, AgRP, adenosine triphosphate, and glycogen in soleus muscle as well as plasma concentrations of the orexigenic hormones. Eighteen adult Wistar male rats (12 weeks old, 235-255 g) were randomly assigned to training (n = 10) and control (n = 8) groups. The training group ran for 60 min/d, 5d/wk at 25 m/min and 0% grade for 6 weeks. Forty-eight hours after the last exercise session, rats were killed; and soleus muscle and plasma were collected and frozen in liquid nitrogen for later analysis. Results demonstrated that 6 weeks of treadmill exercise reduced ghrelin and increased AgRP levels in plasma. Trained rat soleus muscle had higher levels of glycogen but not adenosine triphosphate or AgRP compared with untrained controls. Data indicate that training lowers ghrelin levels in rat soleus and plasma, which is accompanied by higher plasma AgRP and soleus glycogen content.
[Show abstract][Hide abstract] ABSTRACT: هدف: بررسي تشكيل رزت هاي عصبي سلول هاي بنيادي جنيني موش به دنبال ه مكشتي با سومايت هاي جنين جوجه در محيط آزمايشگاهي
به روش قطره آويزان اجسام ش به ،Royan B مواد و روش ها: اين مطالعه به روش تجربي انجام شد.از سلول هاي بنيادي جنيني رده 1
تهيه شدند . سومايت ها از جنين جوجه جدا شده و در محلول آلجينيت قرار داده شدند. در نهايت دانه هاي آلجينيت حاوي (EBs) جنيني
2 اسيد رتينوئيك اضافه شد. -/2+/ ها نيز مطابق با پروتكل + 2 EB هم كشتي داده شدند. به برخي از EB سومايت با
ها شوند در حالي كه اين ميزان در گروه EB 14 % از / يافته ها: سومايت ها توانستند سبب ظهور ساختارهاي رزتي اوليه و بالغ در 56
0/0 درصد بود . رزت ها پس از جداسازي و كشت مجدد توانستند نورون توليد نمايند و مشخص RA 2 درصد و در گروه / كنترل 6
شد كه علاوه بر حضور عوامل القاگر عصبي، گذشت زمان نيز در تشكيل رزت ها نقش دارد.
هاي حاصل از سلول هاي EB نتيجه گيري: سومايت هاي جنين جوجه قادرند در محيط آزمايشگاهي باعث تشكيل ساختار هاي رزتي در
بنيادي جنيني موش شوند كه قابليت توليد نورون را دارند.
[Show abstract][Hide abstract] ABSTRACT: Ghrelin and obestatin both are orexigenic/anorexigenic peptides which are secreted from gastrointestinal tracts (fundus submucosa cells). Obestatin is a 23 amino acid peptide recently isolated from rat stomach, is encoded by the same gene that encodes ghrelin. It has been suggested that ghrelin/obestatin stimulate growth hormone release and have opposite actions on food intake. Distribution and biological activity of obestatin and its role in energy balance were studied in rodents. The purpose of the present study was to investigate fundus and intestine obestatin concentrations and selected hormonal responses to a treadmill exercise running program. Fourteen adult Wistar male rats (12-14 weeks old, 235-250 g) were used for this study. Animals were divided into control (n=7) and training (n=7) groups. Training group was given exercise on a motor-driven treadmill at 25 m/min (0% grade) for 60 min/day, 5 days/week for 6 weeks. Rats were sacrificed 48 h after the last session of exercise fundus, small intestine, and liver were excised, immediately washed in ice-cold saline, and frozen in liquid nitrogen for determination of obestatin and ATP concentrations and liver glycogen content. Plasma was collected for glucose, growth hormone (GH), insulin, and cortisol measurements. Total obestatin concentrations were significantly (P<0.045, P<0.032, respectively) low in trained rat fundus and intestine at rest. Fundus and intestine ATP content remained unchanged. Liver glycogen content was significantly (P<0.039) higher in trained rats. Changes in plasma total obestatin, glucose, insulin, cortisol levels were not significant. Plasma GH concentrations was significantly (P<0.001) higher in trained animals when compared with control rats. The data indicate that moderate treadmill exercise was able to reduce fundus and small intestine total obestatin concentrations and this reduction was accompanied with a higher plasma GH and liver glycogen content in trained rats. Exercise training might modulate fundus and intestine total obestatin levels via an improvement of energy source and a negative feedback action of GH on this peptide.
Biochemical and Biophysical Research Communications 09/2008; 372(4):741-5. DOI:10.1016/j.bbrc.2008.05.097 · 2.30 Impact Factor
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