Hormonal Programming Across the Lifespan

Abstract

Hormones influence countless biological processes across the lifespan, and during developmental sensitive periods hormones have the potential to cause permanent tissue-specific alterations in anatomy and physiology. There are numerous critical periods in development wherein different targets are affected. This review outlines the proceedings of the Hormonal Programming in Development session at the US-South American Workshop in Neuroendocrinology in August 2011. Here we discuss how gonadal hormones impact various biological processes within the brain and gonads during early development and describe the changes that take place in the aging female ovary. At the cellular level, hormonal targets in the brain include neurons, glia, or vasculature. On a genomic/epigenomic level, transcription factor signaling and epigenetic changes alter the expression of hormone receptor genes across development and following ischemic brain insult. In addition, organizational hormone exposure alters epigenetic processes in specific brain nuclei and may be a mediator of sexual differentiation of the neonatal brain. During development of the ovary, exposure to excess gonadal hormones leads to polycystic ovarian syndrome (PCOS). Exposure to excess androgens during fetal development also has a profound effect on the development of the male reproductive system. In addition, increased sympathetic nerve activity and stress during early life have been linked to PCOS symptomology in adulthood. Finally, we describe how age-related decreases in fertility are linked to high levels of nerve growth factor (NGF), which enhances sympathetic nerve activity and alters ovarian function.

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