Objective: To explore possible changes in adrenal steroid metabolism and androgenic-anabolic status in female endurance athletes as a mechanism for their hypercortisolism.
Design: Adrenal steroids and androgenic-anabolic factors were studied during basal conditions and in response to ACTH stimulation related to menstrual status.
Setting: Department of Obstetrics and Gynecology, Karolinska Hospital, Stockholm, Sweden.
Participants: Thirteen female elite middle to long distance runners (six eumenorrheic, seven oligoamenorrheic) and seven regularly menstruating controls.
Interventions: Blood samples were collected before and after an injection of 250 micrograms IV synthetic ACTH 1-24. Body weight, height, and body fat were measured.
Main outcome measures: Basal serum concentrations of cortisol, androstenedione (A), DHEA, DHEAS, 17 alpha-hydroxyprogesterone (17-OHP), T, steroid-binding proteins, and insulin-like growth factor I and ACTH-induced response (area under the curve) of cortisol, DHEA, and 17-OHP.
Results: Oligoamenorrheic athletes had higher basal cortisol and A concentrations compared with healthy controls, whereas basal levels of DHEA and DHEAS were normal. Important findings in the oligoamenorrheic athletes were a significantly lower ratio between the ACTH-induced increments of DHEA and 17-OHP and an increased ratio between basal A and DHEAS. Insulin-like growth factor I was correlated negatively to sex hormone-binding globulin and to the amount of body fat in the combined material.
Conclusions: The results indicate a redistribution of adrenal steroid metabolism in favor of glucocorticoid production in female endurance athletes. We suggest that hypercortisolism in female endurance athletes is a physiological adaptation to maintain adequate blood glucose levels during a condition of energy deficiency.