Reduced meal-related gastrointestinal hormone response to adrenocorticotropic hormone stimulation test in female athletes

Abstract

This study was undertaken to elucidate the impact of hypercortisolism in meal-related gastrointestinal hormone secretion and appetite in female endurance athletes. Thirteen elite runners and seven sedentary women participated on two occasions, either receiving intravenous injection of 250 μg synthetic adrenocorticotropic hormone (ACTH) 1-24 or saline. Blood samples were collected before and after the injection, and then in connection with a standardized meal. Serum concentrations of Cortisol, cholecystokinin (CCK), gastrin, insulin and glucose were analyzed. Self-ratings of appetite were assessed by visual analog scales. Elevated basal levels of Cortisol and glucose were found in the athletes. ACTH-induced Cortisol response was comparable between groups, but a negative correlation between basal Cortisol levels and the ACTH-induced response was found. In sedentary women, ACTH challenge enhanced meal-related CCK and gastrin responses, whereas athletes showed a blunted response of these hormones combined with decreased satiety and reduced levels of insulin. Blunted meal-related response of gastrointestinal hormones and decreased satiety in female runners after ACTH stimulation compared to sedentary women are probably due to differences in the effect of Cortisol, which could be explained by Cortisol insensitivity as a result of basal hypercortisolism in the athletes. Decreased CCK response and satiety in female athletes may reflect increased nutritional requirements.