Estrogenic and Thyroid Regulations in Mammals Are Under Chemical Attack in the Third Millennium

Description

The endocrine system works in concert with the neural regulation to maintain the homeostasis. Metabolism and reproduction are two major pillars of the homeostasis, mostly stemming from the thyroid and steroidogenic systems. These two avenues of the endocrine regulation are evolutionarily strongly conserved, interrelated and tightly linked to genetic functions. They act through nuclear receptors, however, alternative signaling pathways are also known. This work focuses on the mechanisms used by these two systems, nevertheless, some important and functionally strongly linked endocrine mechanisms are discussed to introduce the extreme complexity of the neuroendocrine regulation. Estrogens- and thyroid hormones activate their receptors upon binding, thereby enabling them to bind to the promoter regions of genes possessing hormone responsive elements. Such an action directly regulates gene function. The evolutionary association of the estrogenic and thyroid systems now appear as strong functional interrelationships in higher vertebrates. Effects that alter the function of one of these systems can modulate the function of both systems.