Interactions Between Hormonal and Environmental Signals on Hypothalamic Neurons: Molecular Mechanisms Signaling Environmental Events

It is axiomatic that the central nervous system must manage the integration of several environmental factors with steroid hormonal influences for the biologically adaptive performance of reproductive behavior. Launching from established behavioral investigations and from hormonal influences on gene function in the brain, we review here studies on how synaptic inputs and sex hormone influences codetermine hypothalamic gene expression. A particularly exciting implication of results on the ability of thyroid hormone receptors to interfere with estrogen receptor—dependent neuroendocrine function is that environmentally stimulated changes in thyroid hormone levels could influence hypothalamic transcriptional mechanisms important for behavior. If so, this would unite naturalistic environmental thinking with molecular neurobiological thinking important for the hypothalamic control of reproduction. (Trends Endocrinol Metab 1997;8:111–115). © 1997, Elsevier Science Inc.