The Effects of Long-Term Diabetes on Ghrelin Expression in Rat Stomachs.

BACKGROUND: Ghrelin is a hormone which has effects on the secretion of growth hormone, the gastrointestinal system, the cardiovascular system, cell proliferation and the reproductive system. OBJECTIVES: This study focused on relative ghrelin and GHS-R1a gene expression in the stomach of long-term diabetic rats. MATERIAL AND METHODS: A total of 36 male Wistar albino rats were divided into four groups: a control group, one-month diabetic rats, two-month diabetic rats and three-month diabetic rats. Diabetes was induced by streptozotocin STZ (40 mg/kg i.p). The rats were decapitated under ketamine anesthesia and their stomach tissues were removed. Tissue ghrelin expression, ghrelin and GHS-R mRNA levels were then compared using immunohistochemistry and qRT-PCR. RESULTS: After one month of diabetes, the number of ghrelin-immunopositive cells decreased significantly compared to those of the control rats. However, the ghrelin-immunopositive cells increased numerically in the two- and three-month diabetic rats compared to those of the control rats. It was also observed that there were high levels of ghrelin mRNA in the one- and two-month diabetic rats, and a subsequent decrease of ghrelin mRNA levels in the three-month diabetic rats compared to the control rats. However, ghrelin receptor mRNA expression levels decreased in the one-month diabetic rats, and ghrelin levels subsequently increased in the two- and three-month diabetic rats compared to the control rats. CONCLUSIONS: The two- and three-month diabetic rats became cachectic due to the large amount of weight lost. The authors therefore concluded that ghrelin-immunopositive cells increased in these rats due to their cachectic state.

The effects of streptozotocin-induced diabetes on ghrelin expression in rat testis: biochemical and immunohistochemical study.

INTRODUCTION: Ghrelin is a hormone which has effects on the secretion of growth hormone, gastrointestinal system, cardiovascular system, cell proliferation and reproductive system. The present study we focused on the relation between ghrelin and GHS-R1a gene expression and the regulation of their expression in the testes of diabetic rats. MATERIAL AND METHODS: 40 male Wistar albino rats were divided into four groups: control, and sampled 4, 8 and 12 weeks after induction of diabetes by streptozotocin (STZ) intraperitoneal injection (40 mg/kg). The rats were decapitated under ketamine anesthesia and their testes were removed. Blood was obtained from heart and serum follicle stimulating hormone (FSH), luteinizing hormone (LH), and testosterone levels were measured by ELISA. Tissue ghrelin and GHS-R mRNA levels were determined by qRT-PCR, while ghrelin protein expression was studied by immunohistochemistry. Histopathological damage scores were also assessed. RESULTS: Eight weeks after diabetes induction serum FSH level was increased, whereas LH and testosterone concentrations decreased. The ghrelin and GHS-R1a gene expression and ghrelin immunohistochemistry score first tended to increase after first four weeks of diabetes, and then tended to decrease. Ghrelin-immunopositive cells were detected in Leydig cells in all groups of rats, however, not in the germinal epithelium. Congestion of vessels and hemorrhage, formation of the vacuoles in spermatogonia and spermatocytes, desquamation of spermatids in the lumen and disorganization of seminiferous tubule germinal epithelium were observed in testis of all the diabetic rats. In addition, mean testicular biopsy score and mean seminiferous tubule diameter were getting lower in diabetic animals. CONCLUSION: Our results suggest that diabetes affects ghrelin expression in rat testis.