This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Relative and absolute amounts of body fat are critical for the onset of puberty and subsequent development and maintenance of menstrual cyclicity, ovulation and ultimately fertility. The need for a positive energy balance to ensure reproductive competency and maturity has been supported by studies in both animals and humans. Physical training and increased energy expenditure can induce a decrease of adiposity and a consequent reduction in reproductive competency of otherwise healthy young women. We are using the model of the post-pubertal athlete of normal weight to test the hypothesis that relative fatness is critical to the maintenance of the integrity of the reproductive axis. The experimental design consists of collecting the following: 1) Body composition by DEXA scan 2) VO2 max determination by treadmill 3) Detailed dietary analysis and 4) GCRC admission for 24 hour high frequency blood sampling of gonadotropins, growth hormone cortisol and leptin. In phase 1, we have collected a reference database of over 50 healthy young women in various states of fitness. Now in Phase 2, we now are starting an intervention phase where sedentary but otherwise healthy young women are trained and enrolled in hormonal studies pre and post-training. Future research directions will apply the same research paradigm to the study of insulin-resistant states in adolescent females such polycystic ovary disease with comparison between the effects of physical training, diet and insulin sensitizing agents. This work will help identify markers and cofounders that will ultimately be incorporated in the design of very large epidemiological studies.
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