Study Of Growth Hormone On The Movement In Rat Pancreatic ¦Â Cell Morphology And Function

Objective The present study investigated the possibility and mechanism of the secondary diabetes induced by long time rhGH administration.in training rats. Finding ways to provide theoretical basis for anti-drug education. The indexes we monitored include the density of the blood sugar, serum insulin, serum C-peptide, liver glycogen and muscle glycogen, the morphology of B cells et al.Methods 28 male mature SD rats were randomly divided into 4 groups: i.e. rest group(n=8) , injection group(n=6), exercise group(n=8), exercise plus injection group(n=6). After accustomed for one week; the exercise control group and exercise plus injection group were trained for 8 weeks (grade of 5, at the speed of 20m/min, duration of 1 hour, 6 day/week). Injection protocol: The groups with rhGH-injection were administered with rhGH subcutaneously at 8 p.m. everyday for 4 weeks, (dose: 2.5-3.0mg/kg/d) The resting and exercise control groups were injected the same dose of placebo . Sample collection and measurements were performed after the last injection and a 12-hour fast. The sample we collected includes blood, pancreas, liver and gastrocnemiuses.Results 1 .The blood sugar of the endurance training group rats are significantly lower than that of the rest control group (P<0.001) ,but there is no significant difference between the injection and the non-injection groups. 2. C-peptides increase significantly in the injection groups compared with the non-injection groups. 3. The serum insulin level of the rest injection group is much higher than that of the resting control group ; the level of the exercise plus injection group is much higher than the exercise group ,but the value failed to reach the significant level. 4. C/G of the exercise groups is significantly higher than that of the rest groups. 5. Compared with HBCI, the level of the exercise plus injection group increased more than that of the exercise group; the levels of the rest injection group increased 6. The liver glycogen of the injected groups is lower than the non-injected groups; the level of the exercise control group dropped also. 7. The muscle glycogen of the resting control group is lower than that of the others. 8. The ratio of the areas of p-cell to the pancreatic islets of the injection groups had the trend of increase, but no significant difference observed.Conclusion 1. The result of the increased serum insulin and C-peptide and their unchanged blood sugar of the rhGH administration groups indicate that rhGH can induce insulin resistance. 2. The result of C/G and HBCI showed that rhGH can stimulate insulin secretion.The duration of injection in this study were only 4 weeks. If rhGH were administrated for a longer time, the function of p-cells would be exhausted and induced the secondary diabetes when the higher insulin secretion could not compensate insulin resistance. 3. The result of P-cells' image analysis showed that the percentage of the ratio of the areas of P-cells to the pancreatic islets had the trend of increase, which further illustrated that the administration of rhGH stimulate insulin secretion by p-cell from morphology .