title: Impaired gonadotropin responses to gonadotropin-releasing hormone stimulation in endurance-trained women.
abstract: The effects of endurance running on body composition, menstrual cycles, and gonadotropins were studied in 19 healthy, young, regularly menstruating women. Midfollicular plasma concentrations of unstimulated and gonadotropin-releasing hormone (GnRH)-stimulated luteinizing hormone and follicle-stimulating hormone were examined at baseline and after each subject's weekly mileage had increased 30 miles (delta 30) and 50 miles (delta 50) above baseline. Mean +/- standard error of the mean unstimulated luteinizing hormone and follicle-stimulating hormone did not change significantly. GnRH-stimulated luteinizing hormone was 76.3 +/- 22.0 micrograms/min/ml at baseline and declined to 20.2 +/- 4.5 micrograms/min/ml at delta 50 (P less than 0.02). GnRH-stimulated follicle-stimulating hormone was 28.4 +/- 7.0 micrograms/min/ml at baseline and declined to 9.6 +/- 2.1 micrograms/min/ml at delta 50 (P less than 0.02). There were no significant correlations between changes in body composition and changes in gonadotropin responses. Eighteen subjects developed oligomenorrhea.
mesh_terms: D000328:Adult; D001823:Body Composition; D001835:Body Weight; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006062:Gonadotropins / Q000097:blood*; D006801:Humans; D007986:Luteinizing Hormone / Q000097:blood; D008598:Menstruation; D008875:Middle Aged; D009839:Oligomenorrhea / Q000209:etiology; D010807:Physical Endurance; D010906:Pituitary Hormone-Releasing Hormones / Q000494:pharmacology*; D012420:Running
chemical_list: D006062:Gonadotropins; D010906:Pituitary Hormone-Releasing Hormones; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone