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.
BACKGROUND
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.


METHODS
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).


RESULTS
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).


CONCLUSIONS
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.
Rickenlund
A
A
Department of Woman and Child Health, Division of Obstetrics and Gynecology, Karolinska Institutet, SE-171 76 Stockholm, Sweden. angelica.linden-hirschberg@karolinska.se
Thorén
M
M
Nybacka
A
A
Frystyk
J
J
Hirschberg
A Lindén
AL
D000293:Adolescent; D000328:Adult; D056352:Athletes; D002940:Circadian Rhythm; D003276:Contraceptives, Oral / Q000494:pharmacology* / Q000627:therapeutic use; D005260:Female; D013006:Growth Hormone / Q000097:blood*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D007328:Insulin / Q000097:blood*; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000097:blood*; D008599:Menstruation Disturbances / Q000097:blood* / Q000188:drug therapy
D003276:Contraceptives, Oral; C032231:IGFBP1 protein, human; D007328:Insulin; D018970:Insulin-Like Growth Factor Binding Protein 1; D013006:Growth Hormone; D006854:Hydrocortisone