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

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. This study focused on relative ghrelin and GHS-R1a gene expression in the stomach of long-term diabetic rats. 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. 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. 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.