Chapter 36: Steroid hormones and circumventricular organs

Abstract

This chapter presents evidence for the presence of steroid hormone receptors in circumventricular organs (CVOs) and ependymal specializations that indicates a wide presence of nuclear receptor binding of radiolabeled ligand. Relationships between the increased ventricular surface and the underlying neural structures are demonstrated for the traditional CVOs and can be expected to exist in all of the ventricular outpocketings, including the recess of the locus ceruleus, and the pontine sulcus medianus. The presence of steroid hormone receptors in or near many of these structures adds significance and suggests steroidal control of functions, even though specific functional details remain to be clarified. The chapter presents the presence of steroid binding sites as observed in autoradiograms with radiolabeled hormone from in vivo studies. The presence of steroid hormone receptors in the regions of the OVLT, the SFO and in the interconnecting nuclear groups strongly suggests regulatory effects on brain angiotensin production and secretion and on the related regulation of water and electrolyte homeostasis.