Biomaterial Database

Estradiol is selectively neurotoxic to hypothalamic beta-endorphin neurons. 1993

G C Desjardins, and J R Brawer, and A Beaudet

Department of Anatomy, Montreal Neurological Institute, McGill University, Quebec, Canada.

The neurotoxic effects of estradiol on hypothalamic arcuate neurons were examined in a model of chronic estrogenization induced by means of a single injection of estradiol valerate (EV). Eight weeks after EV treatment, a 60% decrease in the total number of beta-endorphin-immunoreactive neurons was detected in the arcuate nucleus. In contrast, the numbers of neurotensin-, somatostatin-, and tyrosine hydroxylase-immunoreactive neurons were unchanged, suggesting that the effects of estradiol were selective for beta-endorphin neurons. Further evidence for the selectivity of estradiol's actions was provided by RIAs indicating decreases in hypothalamic beta-endorphin concentrations, but not in Metenkephalin or neuropeptide-Y concentrations. Cell counts performed in Nissl-stained material using unbiased stereological methods revealed a reduction in the total number of neurons in the EV-treated group compared to that in the controls. The estimated number of neurons lost (approximately 3500) corresponded precisely with the total number of beta-endorphin neurons lost (approximately 3600), as estimated using quantitative immunocytochemistry. These results confirm the selectivity of estradiol's effect on the beta-endorphin cell population and demonstrate that the observed decrease in beta-endorphin immunoreactivity reflects actual cell loss. The evidence indicates that the selective neurotoxic effect of estradiol on hypothalamic beta-endorphin neurons contributes to reproductive senescence, suggesting that steroids may participate in disruption of the biological functions that they normally facilitate.

UI	MeSH Term	Description	Entries
D007031	Hypothalamus	Ventral part of the DIENCEPHALON extending from the region of the OPTIC CHIASM to the caudal border of the MAMMILLARY BODIES and forming the inferior and lateral walls of the THIRD VENTRICLE.	Lamina Terminalis,Preoptico-Hypothalamic Area,Area, Preoptico-Hypothalamic,Areas, Preoptico-Hypothalamic,Preoptico Hypothalamic Area,Preoptico-Hypothalamic Areas
D009474	Neurons	The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.	Nerve Cells,Cell, Nerve,Cells, Nerve,Nerve Cell,Neuron
D009478	Neuropeptide Y	A 36-amino acid peptide present in many organs and in many sympathetic noradrenergic neurons. It has vasoconstrictor and natriuretic activity and regulates local blood flow, glandular secretion, and smooth muscle activity. The peptide also stimulates feeding and drinking behavior and influences secretion of pituitary hormones.	Neuropeptide Y-Like Immunoreactive Peptide,Neuropeptide Tyrosine,Neuropeptide Y Like Immunoreactive Peptide,Tyrosine, Neuropeptide
D009496	Neurotensin	A biologically active tridecapeptide isolated from the hypothalamus. It has been shown to induce hypotension in the rat, to stimulate contraction of guinea pig ileum and rat uterus, and to cause relaxation of rat duodenum. There is also evidence that it acts as both a peripheral and a central nervous system neurotransmitter.
D002452	Cell Count	The number of CELLS of a specific kind, usually measured per unit volume or area of sample.	Cell Density,Cell Number,Cell Counts,Cell Densities,Cell Numbers,Count, Cell,Counts, Cell,Densities, Cell,Density, Cell,Number, Cell,Numbers, Cell
D004744	Enkephalin, Methionine	One of the endogenous pentapeptides with morphine-like activity. It differs from LEU-ENKEPHALIN by the amino acid METHIONINE in position 5. Its first four amino acid sequence is identical to the tetrapeptide sequence at the N-terminal of BETA-ENDORPHIN.	Methionine Enkephalin,5-Methionine Enkephalin,Met(5)-Enkephalin,Met-Enkephalin,5 Methionine Enkephalin,Enkephalin, 5-Methionine,Met Enkephalin
D004958	Estradiol	The 17-beta-isomer of estradiol, an aromatized C18 steroid with hydroxyl group at 3-beta- and 17-beta-position. Estradiol-17-beta is the most potent form of mammalian estrogenic steroids.	17 beta-Estradiol,Estradiol-17 beta,Oestradiol,17 beta-Oestradiol,Aerodiol,Delestrogen,Estrace,Estraderm TTS,Estradiol Anhydrous,Estradiol Hemihydrate,Estradiol Hemihydrate, (17 alpha)-Isomer,Estradiol Monohydrate,Estradiol Valerate,Estradiol Valeriante,Estradiol, (+-)-Isomer,Estradiol, (-)-Isomer,Estradiol, (16 alpha,17 alpha)-Isomer,Estradiol, (16 alpha,17 beta)-Isomer,Estradiol, (17-alpha)-Isomer,Estradiol, (8 alpha,17 beta)-(+-)-Isomer,Estradiol, (8 alpha,17 beta)-Isomer,Estradiol, (9 beta,17 alpha)-Isomer,Estradiol, (9 beta,17 beta)-Isomer,Estradiol, Monosodium Salt,Estradiol, Sodium Salt,Estradiol-17 alpha,Estradiol-17beta,Ovocyclin,Progynon-Depot,Progynova,Vivelle,17 beta Estradiol,17 beta Oestradiol,Estradiol 17 alpha,Estradiol 17 beta,Estradiol 17beta,Progynon Depot
D005260	Female		Females
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001111	Arcuate Nucleus of Hypothalamus	A nucleus located in the middle hypothalamus in the most ventral part of the THIRD VENTRICLE near the entrance of the infundibular recess. Its small cells are in close contact with the EPENDYMA.	Arcuate Nucleus,Infundibular Nucleus,Hypothalamus Arcuate Nucleus,Nucleus, Arcuate,Nucleus, Infundibular