Endocrine Abstracts

Introduction: A well known side effect of glucocorticoid treatment is abdominally centred weight gain due to increased sensation of hunger but the underlying mechanism is still only incompletely clarified. To elucidate whether the brain reward system is involved in this regulation we studied here the effects of an acute prednisolone infusion on brain centres responding to food stimulation by fMRI in healthy males and correlated these findings to the 24 h food intake of the subjects.

Methods:: 20 healthy normal-weight men were tested in a prospective randomized cross-over setting after an overnight fast respectively. They were either infused for 30 min with 250 mg prednisolone or placebo. fMRI scans were taken 4 h later while presenting food and object pictures. At the following morning participants had a supervised breakfast at a standardized buffet. All were restricted from eating during the four hours until fMRI and kept a food diary until the next morning.

Results: When presenting palatable food pictures in contrast to object pictures we obtained a significant activation in brain regions known to be part of the food reward system like the hippocampus, anterior cingulate cortex, bilateral amygdala and insula. Application of prednisolone significantly increased the activity in the bilateral amygdala and right insula in contrast to placebo. The buffet test did not reveal any significant difference in calorie intake or preferences of different macronutrients nor did the food diary.

Discussion: The present imaging results support a direct stimulatory, prednisolone specific effect on food reward centres in the bilateral amygdala and the right insula. This interaction may represent an increased anticipated reward value of high calorie food mediated by glucocorticoids, an effect which most likely needs to be present for a prolonged period of time to relate to a measurably increased food intake (supported by DFG).