Effects of oral contraceptives on diurnal profiles of insulin, insulin-like growth factor binding protein-1, growth hormone and cortisol in endurance athletes with menstrual disturbance
Rickenlund, A.; Thorén, M.; Nybacka, A.; Frystyk, J.; Hirschberg, A.L.én.
Human Reproduction 25(1): 85-93
2010
ISSN/ISBN: 1460-2350 PMID: 19840988 DOI: 10.1093/humrep/dep350Document Number: 207836
Menstrual disturbances in female athletes are often explained as a consequence of energy deficiency. Oral contraceptive (OC) treatment may have favorable metabolic effects. We evaluated effects of OCs on diurnal secretions of insulin, insulin-like growth factor binding protein 1 (IGFBP-1), growth hormone (GH) and cortisol in relation to changes in body composition in athletes with menstrual disturbance compared with regularly menstruating athletes and controls. Age- and BMI-matched groups of endurance athletes with menstrual disturbance (OAM, n = 9) and regularly cycling athletes (RM, n = 8) and sedentary controls (CTRL, n = 8) were examined, and hormone levels measured, before and after 8 months of treatment with a low-dose combined OC (30 microg ethinyl estradiol + 150 microg levonorgestrel). Before OC treatment, the diurnal profile of insulin was lower (P < 0.01) and levels of IGFBP-1 (P < 0.05) and cortisol (P < 0.05) were higher in OAM athletes than in CTRL, whereas GH secretion was higher than in RM athletes (P < 0.05). After treatment, diurnal secretions of these hormones were similar between groups with an increase of IGFBP-1 in the regularly menstruating subjects only (P < 0.001). OC treatment increased body fat mass in OAM athletes (P < 0.01 versus baseline). The change in total fat mass correlated positively with pretreatment diurnal levels of GH (r(s) = 0.67, P < 0.01) and cortisol (r(s) = 0.64, P < 0.01). OC treatment in endurance athletes with menstrual disturbance increases body fat mass and results in diurnal levels of insulin, IGFBP-1, GH and cortisol that are comparable to those in regularly menstruating subjects. These results suggest that OCs improve metabolic balance in OAM athletes.