Amenorrhea, Anovulation, Infertility, Starvation
Conditions
Keywords
LH pulsatility, energy availability, exercise, diet, gynecological age
Brief summary
The purpose of this experiment is to investigate whether the dependence of luteinizing hormone pulsatility on energy availability declines during adolescence.
Detailed description
The incidence of menstrual disorders declines during adolescence. This has long been attributed to the gradual maturation of the hypothalamic-pituitary-ovarian axis, but the mechanism of this maturation is not known. Ovarian function critically depends on the pulsatile secretion of gonadotropin-releasing hormone (GnRH) by the hypothalamus and on the consequent and more readily assessed pulsatility of luteinizing hormone (LH) secretion by the pituitary. LH pulsatility has been shown to depend on energy availability, operationally defined as dietary energy intake minus exercise energy expenditure. The effects of energy availability on LH pulsatility are thought to be mediated by certain metabolic substrates and hormones. Comparison: By manipulating diet and exercise regimens, contrasting energy availability treatments of 10 and 45 kilocalories per kilogram of fat-free mass per day are being administered to adolescents with 5-8 years of gynecological age and to adults with 14-18 years of gynecological age for five days in the early follicular phase of separate menstrual cycles. Effects of low energy availability on LH pulsatility and on selected metabolic substrates and hormones are being measured.
Interventions
BEHAVIORALEnergy availability
Sponsors
Ohio State University
Ohio University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
PREVENTION
Masking
NONE
Eligibility
Sex/Gender
FEMALE
Age
18 Years to 34 Years
Healthy volunteers
Yes
Inclusion criteria
* 5-8 or 14-18 years of gynecological age * menstrual cycles of 26 to 32 days for the previous 3 months * luteal phase length \>11 days * 18-32% body fat
Exclusion criteria
* smoking * oral contraceptives * hematocrit \<35% * diet with \<35 or \>55 kcal/kgFFM/day of energy * habitually performing more than 60 minutes/week of aerobic exercise * histories or evidence of heart, liver, or kidney disease, diabetes, menstrual or thyroid disorders, pregnancy, lactation, and congenital or acquired orthopedic abnormalities
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Differences in 24h LH pulse frequency, 24h LH pulse amplitude and 24h LH mean concentration in blood samples drawn q10' for 24 hours after 5 days of treatment | — |
Secondary
| Measure | Time frame |
|---|---|
| Differences in 24h average glucose, beta-hydroxybutyrate, insulin, cortisol, growth hormone, insulin-like growth factor-I, tri-iodothyronine, and leptin concentrations in blood samples drawn q10' for 24 hours after 5 days of treatment | — |
Countries
United States
Outcome results
None listed