Aydin, Suleyman; Kuloglu, Tuncay; Aydin, Suna; Eren, Mehmet Nesimi; Yilmaz, Musa; Kalayci, Mehmet; Sahin, Ibrahim; Kocaman, Nevin; Citil, Cihan; Kendir, Yalcin

We have investigated how diabetes affects the expression of adropin (ADR) in rat brain, cerebellum, kidneys, heart, liver, and pancreas tissues. The rats in the diabetic group were administered an intraperitoneal (i.p.) injection of a single dose of 60 mg/kg streptozotocin (STZ) dissolved in a 0.1 M phosphate-citrate buffer (pH 4.5). The rats were maintained in standard laboratory conditions in a temperature between 21 and 23 C and a relative humidity of 70 %, under a 12-h light/dark cycle. The animals were fed a standard commercial pellet diet. After 10 weeks, the animals were sacrified. ADR concentrations in the serum and tissue supernatants were measured by ELISA, and immunohistochemical staining was used to follow the expression of the hormones in the brain, cerebellum, kidneys, heart, liver, and pancreas tissues. The quantities were then compared. Increased ADR immunoreaction was seen in the brain, cerebellum, kidneys, heart, liver, and pancreas in the diabetes-induced rats compared to control subjects. ADR was detected in the brain (vascular area, pia mater, neuroglial cell, and neurons), cerebellum (neuroglial cells, Purkinje cells, vascular areas, and granular layer), kidneys (glomerulus, peritubular interstitial cells, and peritubular capillary endothelial cells), heart (endocardium, myocardium, and epicardium), liver (sinusoidal cells), and pancreas (serous acini). Its concentrations (based on mg/wet weight tissues) in these tissues were measured by using ELISA showed that the levels of ADR were higher in the diabetic rats compared to the control rats. Tissue ADR levels based on mg/wet weight tissues were as follows: Pancreas > liver > kidney > heart > brain > cerebellar tissues. Evidence is presented that shows ADR is expressed in various tissues in the rats and its levels increased in STZ-induced diabetes; however, this effect on the pathophysiology of the disorder remains to be understood.

Aydin, Suleyman; Sahin, Ibrahim; Ozkan, Yusuf; Dag, Ersel; Gunay, Ahmet; Guzel, Saadet Pilten; Catak, Zekiye; Ozercan, Mehmet Resat

Currently, obesity is an important health problem in all countries, both developed and developing. Dietary habits and neurohormonal imbalances play a critical role in obesity. Circulating amounts of ghrelin, which is a neurohormonal hormone, decrease with obesity and increase with weight loss. Although it is known that both mRNA and peptide version of the ghrelin hormone are expressed in almost all tissues of both humans and animals, it is not known how obesity changes the expression of this hormone in the tissues, with the exception of the gastrointestinal system tissues. Therefore, the objective of the present study is to show how diet-induced obesity in rats changes ghrelin expression in all system tissues, and thus, to shed light on the etiopathology of obesity. The study included 12 male and 12 female 2-month-old Wistar albino species rats. The animals in the control group were fed on standard rat pellet, while those in the experiment group were fed ad libitum on a cafeteria-style diet for 2 months. When their body mass index reached 1 g/cm 2, diet-induced obese (DIO) rats were sacrificed in a sterile environment after one night fasting. Ghrelin localizations in the tissues were studied immunohistochemically using avidin-biotin-peroxidase complex (ABC) method, while tissue ghrelin amounts were analyzed using radioimmunoassay (RIA) method. When the ghrelin amounts in the urogenital system (with the exception of kidney tissues), sensory organs, respiratory system, immune system, skeletal muscle system, cardiovascular system, nervous system, and adipose tissue of rats analyzed by RIA method were compared to those in the control group, tissue ghrelin amounts in the DIO group were found lower. Immunohistochemical findings which showed a similar fall in ghrelin concentrations in the tissues were parallel to RIA results. In addition, ghrelin was shown to be synthesized in the cardiovascular system, heart muscle cells, tails of the sperms, hair follicles, lacrimal glands, tongue, and teeth of rats for the first time in this study and ghrelin syntheses in these tissues were found to decrease in obesity. Nutritional obesity is among the most common causes of obesity and the findings we have obtained through diet-induced obesity will contribute to the illumination of the etiopathology of obesity.

Sahin, Ibrahim; Aydin, Suleyman; Ozkan, Yusuf; Dagli, Adile Ferda; Akin, Kadir Okhan; Guzel, Saadet Pilten; Catak, Zekiye; Ozercan, Mehmet Resat

The aims of the present study were to examine ghrelin expression in serum and gastrointestinal tract (GIT) tissues, and to measure tissue ghrelin levels and obesity-related alterations in some serum biochemical variables in rats with diet-induced obesity (DIO). The study included 12 male rats, 60 days old. The rats were randomly allocated to two groups (n = 6). Rats in the DIO group were fed a cafeteria-style diet to induce obesity, while those in the control group were fed on standard rat pellets. After a 12 week diet program including an adaptation period all rats were decapitated, tissues were individually fixed, ghrelin expression was examined by immunohistochemistry, and tissue and serum ghrelin levels were measured by radioimmunoassay. Serum biochemical variables were measured using an autoanalyzer. When the baseline and week 12 body mass index and GIT ghrelin expression were compared between DIO and control rats, BMI had increased and ghrelin expression decreased due to obesity. The RIA results were consistent with these findings. Serum glucose, LDL cholesterol, and total cholesterol levels were elevated and HDL cholesterol significantly decreased in the DIO group. A comparison of GIT tissues between the control and obese groups demonstrated that ghrelin was decreased in all tissues of the latter. This decrease was brought about a decline in the circulating ghrelin pool. This suggests that rather than being associated with a change in a single tissue, obesity is a pathological condition in which ghrelin expression is changed in all tissues.