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

Abstract

Ghrelin is ahormone 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. Atotal of 36 male Wistar albino rats were divided into four groups: acontrol 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-RmRNA 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 asubsequent 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.