The investigation of ghrelin organ distribution maps and serum ghrelin, paraoxonase and arylesterase levels in the diet-induced obese rats

In this study, obesity was induced in rats to determine ghrelin expressions by tissues, levels of ghrelin in the serum and tissues, as well as PON1 and AE levels and their correlations with levels of some serum biochemical parameters. 60-day-old 24 rats (12 male and 12 female) were included in the study. The rats were randomly allocated to 4 groups (n:6), in consideration of their sexes. In order to induce obesity by diet, the rats in Diet-Induced Obesity group (DIO) were fed on cafeteria-style diet, while the rats in the control group were fed on standard rat pellet. After DIO was formed with 12 weeks long adaptation and diet programs, all rats were sacrificed. When rats? tissues were separated according to the systems, their ghrelin expressions were determined by immunohistochemical (IHC) method, and tissue and serum ghrelin levels by radioimmunoassay (RIA) method. Tissue and serum PON1 and AE levels were measured by spectrophotometric method. Serum biochemical parameters were studied by an autoanalyzer.When basal and 12. weeks BMI and ghrelin expressions by whole systems tissues of the rats with diet-induced obesity were compared to those of the control group, BMI were found to rise, while ghrelin expressions were found to drop in obesity. As an exception, ghrelin expression in the kidney tissue was observed to increase. These findings were confirmed by RIA results. In addition to tissues known to express ghrelin, some new tissues (tongue, teeth, hair follicle, lacrimal gland, and sperm tail) were found to express ghrelin, as well. Tissue and serum PON1 and AE levels exhibited a trend similar to IHC findings. Glucose, LDL-cholesterol and total cholesterol levels were observed to significantly increase and HDL-cholesterol was observed to significantly decrease in the DIO group.