Plasma apelin, insulin, and adiponectin levels in normal and diet-induced obese mice

Plasma Apelin, Insulin, and Adiponectin Levels in Normal and Diet-Induced Obese Mice There are many factors involved in the physiopathological processes of obesity-related diabetes, and their exact relationships are still not understood. Explaining how insulin resistance develops during the obesity is important in terms of effective treatment of obesity-related diabetes. This study aimed to investigate the changes in plasma levels of apelin, insulin, and adiponectin and to investigate their relationships with each other in case of a dietary induced obesity model. Twenty four male Swiss albino mice all 6 week old males were randomly divided into two groups obese and control. During 18 weeks of experiment, mice in the obese group were fed a high-fat diet (28.2%) and those in control group were given a standard diet. Body weights and food consumptions were recorded weekly and monthly, respectively. At the end of the study, blood samples were obtained under anesthesia via intra cardiac punction. Plasma apelin, insulin, and adiponectin concentrations were determined by ELISA. At the end of the 18-weeks interventional period, the mean body weights of the mice in obese group was 47% higher, compared to those in control group (P<0.001). Plasma apelin and insulin levels showed no difference (P>0.05), whereas the mean adiponectin level of obese mice was lower than the mean of the controls mice (P=0.05). Despite the fact that plasma apelin and insulin levels were not affected by diet-induced obesity, a strong positive correlation was found between apelin, insulin, and adiponectin concentrations (P<0.001). Moreover, correlation analysis in each group showed a significant relationship between apelin and insulin concentrations both in control (P<0.001) and obese (P<0.05) groups. The data show, at least this obesity model, that obesity is not the major determinant in terms of the rise of apelin and insulin. However, correlation analysis indicates that apelin has beneficial effects on insulin variation. Key Words: Apelin, insulin, obesity, mouse.