The investigation of the effect of Enalapril and Losartan on Ghrelin immunreactivity on kidneys of the rats with experimental diabetes

Diabetes mellitus is characterised with high blood glucose levels and disorders of carbonhydrate, protein, and lipid metabolisms. Diabetes mellitus affects more and more people worldwide and one of the most important morbidity and mortality cause of diabetes is diabetic nephropathy. Renal protective effects of enalapril and losartan by inhibition of oxidation pathways and reducing proteinuria is known.Ghrelin is an endogenous peptide, which stimulates the growth hormone secretion, is secreted by most of the tissues includes kidneys. Recently, it is assumed that ghrelin, which is a regulatory peptide, can have role in the pathogenesis of diabetes mellitus.In this study, we investigated the effects of losartan and enalapril which are used as therapeutic agents in diabetic nephropathy on immunreactivity of ghrelin.We used 28 Wistar albino rats that were 6 weeks age and 210 ? 20 gr weight. We fed all groups for 4 weeks with standard food and water. In control group, (Group 1) no intervention was executed. In other 3 groups, 50 mg/kg streptozocin solved in 0,1 M phosphate-citrate buffer (pH 4.5) was injected intraperitoneally. After the establishment of experimental diabetes mellitus we determined the diabetes group (Group 2) and no intervention was executed to this group. In diabetes + enalapril group (Group 3), we administered 5 mg/kg/day enalapril via orogastric catether for 4 weeks. Diabetes+losartan group (Group 4), we administered 10 mg/kg/day losartan via orogastric catether for 4 weeks. After the experiments rats were decapitated and renal tissues were taken out. With routine light microscope observation, tissues were intered into paraphine blockes stained with histologic coloures and for ghrelin immunreactivity ``avidin-biotin-peroxidase?? method was applied.With immunohistochemical stain, we observed moderate (++) ghrelin immunreactivity on distal tubuli. In experimentally diabetes group, we observed severe (+++) ghrelin immunreactivity on renal cortex and renal medulla distal tubuli. In treatment groups (Group 3 and Group 4), ghrelin immunreactivity in renal cortex and medulla was similar to control group, and moderate (++) ghrelin immunreactivity was observed in distal tubuli.There is relationship between diabetes mellitus and ghrelin. In diabetic group, ghrelin immunreactivity was high. In both treatment groups, ghrelin immunreactivity was low in comparison with diabetic group. In conclusion, we determined that enalapril and losartan administration has effects on ghrelin expression in renal tissue of diabetic rats and more comprehensive studies are needed on this issue.Key Words: Diabetes mellitus, enalapril, losartan, ghrelin