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.
Department of Woman and Child Health, Division of Obstetrics and Gynecology, Karolinska Institutet, SE-171 76 Stockholm, Sweden. angelica.linden-hirschberg@karolinska.se
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A
Rickenlund
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Thorén
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Nybacka
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Frystyk
A Lindén
AL
Hirschberg
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