Estrogen receptor-β in oxytocin and vasopressin neurons of the rat and human hypothalamus: Immunocytochemical and in situ hybridization studies

• Published in: Journal of comparative neurology (1911) 2004-05, Vol.473 (3), p.315-333
• Main Authors: Hrabovszky, Erik, Kalló, Imre, Steinhauser, Annamária, Merchenthaler, István, Coen, Clive W., Petersen, Sandra L., Liposits, Zsolt
• Format: Article
• Language: English
• Subjects: Adult; Aged; Animals; corticotropin releasing hormone; Corticotropin-Releasing Hormone - genetics; Corticotropin-Releasing Hormone - metabolism; estradiol; Estrogen Receptor beta; Female; Humans; Hypothalamus - cytology; Immunohistochemistry - methods; In Situ Hybridization - methods; magnocellular neurons; Male; Microscopy, Electron - methods; Neurons - metabolism; Neurons - ultrastructure; Oxytocin - metabolism; Paraventricular Hypothalamic Nucleus - ultrastructure; paraventricular nucleus; paraventricular nucleus, parvicellular neuron; parvicellular neuron; Postmortem Changes; Rats; Rats, Sprague-Dawley; Receptors, Estrogen - genetics; Receptors, Estrogen - metabolism; Reverse Transcriptase Polymerase Chain Reaction - methods; RNA, Messenger - biosynthesis; supraoptic nucleus; Vasopressins - metabolism
• ISSN: 0021-9967; 1096-9861
• DOI: 10.1002/cne.20127

Topographical distribution of estrogen receptor‐β (ER‐β)‐synthesizing oxytocin (OT) and vasopressin (VP) neurons was studied in the hypothalamic paraventricular and supraoptic nuclei (PVH; SO) of ovariectomized rats. In distinct subregions, 45–98% of OT neurons and 88–99% of VP neurons exhibited ER‐β immunoreactivity that was confined to cell nuclei. Neuronal populations differed markedly with respect to the intensity of the ER‐β signal. Magnocellular OT neurons in the PVH, SO, and accessory cell groups typically contained low levels of the ER‐β signal; in contrast, robust receptor labeling was displayed by OT cells in the ventral subdivision of medial parvicellular subnucleus and in the caudal PVH (dorsal subdivision of medial parvicellular subnucleus and lateral parvicellular subnucleus). Estrogen receptor‐β signal was generally more intense and present in higher proportions of magnocellular and parvicellular VP vs. OT neurons of similar topography. Immunocytochemical observations were confirmed via triple‐label in situ hybridization, an approach combining use of digoxigenin‐, fluorescein‐, and 35S‐labeled cRNA hybridization probes. Further, ER‐β mRNA was also detectable in corticotropin‐releasing hormone neurons in the parvicellular PVH. Finally, double‐label immunocytochemical analysis of human autopsy samples showed that subsets of OT and VP neurons also express ER‐β in the human. These neuroanatomical studies provide detailed information about the topographical distribution and cellular abundance of ER‐β within subsets of hypothalamic OT and VP neurons in the rat. The variable receptor content may indicate the differential responsiveness to estrogen in distinct OT and VP neuronal populations. In addition, a relevance of these findings to the human hypothalamus is suggested. J. Comp. Neurol. 473:315–333, 2004. © 2004 Wiley‐Liss, Inc.