Research Of Effects To The STZ Diabetic Rats Of Pro-Pro-hGHRH(1-44)OH

Title:Research of effects to the STZ diabetic rats of Pro-Pro-hGHRH(1-44)OHObjective: To testify the biological activity of Pro-Pro-hGHRH(1-44)OH and observe the effect of Pro-Pro-hGHRH(1-44)OH to GHRH-GH-IGF-1 axis of STZ diabetic rats Methods: (1)After we took off 6 pituitaries of normal rats, every pituitary was cut into 3 pieces incubated in vitro. All pituitaries were randomly divided into four groups, we added respectively Pro-Pro-hGHRH(1-44)OH 0.01,0.1,1.0 mg·L-1 and hGHRH 2.0 mg·L-1 into the incubation buffer of the four groups ,measured GH concentration . (2)DM rats were divided into 3 groups randomly. Group GHRH analog: treated with Pro-Pro-hGHRH (1-44) OH 1 mg·L-1 i.p.; Group GHRH: treated with hGHRH 2mg·L-1 i.p.; Group DM control: treated with 0.9% NS. Then we measured the GH,IGF-1,insulin concentrations of the three groups and normal control, then compared the effect differences.Other diasbetic related pathophysiologic parameters such as blood glucose,blood lipid ,kidney weight /body weight ratio,blood urea nitrogen serum creatine were observed as well ,respectively. Compare the effect difference of all groups.Results: 1,GH net concentrations of Pro-Pro-hGHRH(1-44)OH(0.01,0.1,1.0mg·L-1) and hGHRH 2.0 mg·L-1 were (2.0±1.3),(8.1±2.7),(12.5±3.2),(4.0±0.3)mIU·ml-1, Pro-Pro-hGHRH(1-44)OH0.1 vs 1.0 mg·L-1 vs hGHRH 2.0 mg·L-1,p<0.05.2,The insulin concentrations of Group GHRH analog,Group GHRH,Group DM control and normal control were respectively (9.929±6.1714),(8.2800±1.1265),(8.0667±3.3148),(18.9625±1.3789) mIU·ml-1.Normal control vs three DM groups,p<0.01. The IGF-1 concentrations of four groups were respectively (199.5057±31.4978),(198.3871±48.1012),(231.3733±50.6731),(242.4450±28.0317) mIU·ml-1。p>0.05 compared between any two groups. The GH concentrations of four groups were respectively (0.7214±0.08513),(0.6429±0.05964),(0.5400±0.05292),(0.7600±0.05715) mIU·ml-1.Group DM control vs normal control, Group GHRH analog vs Group GHRH vs Group DM control,p<0.05. The concentration of blood glucose, blood TC, blood TG, blood urea nitrogen, DM group vs normal control ,p<0.05. The concentration of serum creatine, kidney, DM group vs normal control, p>0.05. Kidney weight,p,0.05 between any two groups except group GHRH analog vs group GHRH.Kidney weight /body weight ratio,p<0.01 between any two groups.Conclusion: Pro-Pro-hGHRH (1-44) OH is a new GHRH analog with potent GH-releasing ability than hGHRH in dose-dependent manner.In STZ DM model, Pro-Pro-hGHRH (1-44) OH can increase greatly GH sensitivity, but IGF-1 does not increase greatly like GH does.