ABSTRACT
It has been demonstrated that plasma ghrelin is likely affected by stress, but little attention has been paid to the effect of stress on ghrelin release from pancreatic islets. This study investigates the effect of stress on ghrelin secretion from pancreatic islets in rats. Male Wistar rats were divided into control and stressed groups. The stressed group was further divided into foot-shock and psychological stress subgroups. Stress was induced by a communication box. After stress exposure, blood sampling was performed to determine the plasma levels of corticosterone, glucose, and ghrelin. Then the animals' pancreatic islets were isolated to assess their ghrelin output at 5.6, 8.3, and 16.7 mM glucose concentrations. Acute exposure to foot-shock and psychological stress both increased plasma corticosterone concentration. Moreover, plasma glucose concentration increased in the foot-shock stress group. Chronic exposure to foot-shock decreased plasma ghrelin concentration, whereas acute exposure had no significant effect. Acute and chronic exposure to foot-shock and psychological stress increased ghrelin secretion from isolated islets in the presence of different glucose concentrations. The results of the present study suggest that ghrelin secretion from isolated islets is not glucose-dependent. However, ghrelin secretion appears to be intensely responsive to both acute and chronic stress.
