A longitudinal analysis of hypothalamic-pituitary-adrenal axis and metabolic energy interactions pre- and post-menarche within and among Mayan Indigenous adolescent girls.

Adolescent girls face significant energetic trade-offs resulting from the concurrent demands of somatic growth and reproductive maturation. The hypothalamic pituitary-adrenal axis (HPAA) is a mediator of energy allocation. However, its longitudinal role during this critical transition is unclear. Hypothesis: HPAA activity should be positively linked with energy mobilization and inversely linked with energy storage, both pre- and post-menarche. We quantified first morning urine biomarkers of HPAA activity (cortisol), potential energy uptake (c-peptide), and energy storage (adiponectin) collected pre-to post-menarche from 46 Mayan girls. We used mixed effects models to characterize HPAA activity and metabolic energy status across menarche stages. Adiponectin and c-peptide were higher pre- versus post-menarche (p < 0.001) after adjusting for cortisol and time relative to menarche. Cortisol was positively associated with both c-peptide and adiponectin after adjusting for time relative to menarche (p < 0.001). Consistent with our hypothesis, HPAA activity was positively linked to energy mobilization across the adolescent transition. Energy uptake was higher pre-menarche, a possible response to energetic demands imposed by somatic and reproductive maturation. Energy storage was higher post-menarche, which may help meet future reproductive energy needs. Understanding changes in energy metabolism during the adolescent transition is paramount to optimizing women's development and health across their life span.