A mechanistic model for endocrine profiles of female puberty maturation

The hypothalamus-pituitary-gonadal axis (HPG axis) has a central role for female reproduction. During pubertal development, the reactivation of the HPG axis causes characteristic physical and psychological changes. Pubertal development is clinically monitored by breast development. However, a trend of earlier breast development in girls is reported since 1977. Hence, the necessity to establish new references to classify pubertal development. Our aim is to set up a mechanistic model that can be used to make predictions about pubertal maturation given the current hormone state and the age. The model consists of ordinary differential equations (ODE) describing the time courses of the main hormones GnRH, LH, FSH, and E2. We assume that all feedback mechanisms of the HPG axis exist from early childhood on and that the main pacemaker for pubertal maturation is the development of a regular GnRH release pattern.Deterministic simulation results are comparable to data. Simulations with sampled parameters reflect inter-individual variability. In future work, we plan to set up an “average model” as a prior using longitudinal hormone data and take individual hormone time series to estimate individual model parameters.