| According to the report of World Health Organization in 1999, diabetes is the third leading cause threatening the public health among chronic noninfectious diseases. In China, the prevalence of diabetes was 0.67% in 1980 and rose to 3.21% in 1995. With the number of diabetic patients increasing and their longevity extending, chronic complications are the emphasis of diabetic treatment, which not only severely affect the quality of living but also contribute greatly to the death of diabetes. It has theoretical meaning and clinical value to study the mechanism of chronic complications and find effective treatment.The development and progress of diabetic chronic complications are collective results of many factors including gene, hyperglycemia, cytokines, growth factors and so on. Recent studies show that the axis of growth hormone (GH)/insulin-like growth factor I (IGF-I) is abnormal in diabetes, which can be involved in the development and progress of diabetic microangiopathy. It is one of the researching directions to correct the abnormality of GH/IGF-I axis and so improve metabolic conditions and chronic complications.Astrugalus is one of traditional Chinese medicines, which is used to treat diabetes. Astrugalus polysaccharide (APS) is one of important effective components of astrugalus. Our previous studies showed that APS could lower blood glucose and GH level and increase IGF-I of diabetic rats. This study is to research the changes of GH/IGF-I axis and its mechanismin streptozotocin (STZ)-induced diabetic rats and then investigate the effects of APS on GH/IGF-I axis and its mechanism. It will provide scientific bases for clinical use of APS to treat diabetes and its complications.Prat I The abnormality of GH/IGF-I axis in STZ diabetic rats Objective: To study the change of GH/IGF-I axis in STZ diabetic rats and its mechanism and to provide bases for research on diabetic chronic complications.Methods: 1. Streptozotocin was used to establish diabetic rat model and a group of normal rats was set up. After 8 weeks, rats were killed and samples were collected. 2. Serum lipids, IGF-I, GH and other indexes were measured by biochemical and radioimmunological methods. 3. Serum insulin-like growth factor binding protein-3 was examined by Western blot and enchanced chemiluminescence detection. 4. The expression of pituitary GH, hepatic IGF-I, IGFBP-3 and GH receptor (GHR) mRNA was detected by RT-PCR.Results: 1. Compared with normal rats, blood glucose and fructosamine of diabetic rats rose significantly (p<0.001). Serum Cholesterol (CHO), triglyceride and low density lipoprotein (LDL) were higher than the normal group (p<0.01). 2. Compared with normal rats, serum GH of diabetic rats rose by 87.9% (p<0.001)and the expression of GH mRNA in pituitary was high. In contrast, serum IGF-I and its gene expression in theliver were lowered than that in normal rats. 3. In diabetic rats, serum concentration of IGFBP-3 and gene expression of IGFBP-3 and GHR in the liver were lower than the normal group (p<0.001).Conclusions: The GH/IGF-I axis of diabetic rats is abnormal and characterized by elevation of GH and reduction of IGF-I and IGFBP-3 in circulation. These abnormalities are associated with hyperglycemia, GH resistance of liver and enhanced GH expression of pituitary. Part â…¡The effect of APS on GH/IGF-I axis in diabetic ratsObjective: To research the mechanism of APS improving the abnormality of GH/IGF-I axis and provide scientific bases for clinical use of APS to treat diabetes and its complications.Mothods: 1. STZ-induced diabetic rats were divided into three groups at random. There were diabetic group (DC), APS therapy group, insulin therapy group and normal rat group (NC). APS group was given APS 1g/kg/day by gavage and INS group was injected insulin every day. All rats were killed after 8 weeks and samples were collected. 2. Serum lipids, IGF-I, GH, c peptide fructosamine and other indexes we...
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