The 4-hydroxyestrone: Electron emission, formation of secondary metabolites and mechanisms of carcinogenesis.

Autor: Getoff N; The University of Vienna, Faculty of Life Science, Section Radiation Biology, A-1090 Vienna, Althanstrasse 14, UZA II, Austria. nikola.getoff@univie.ac.at, Gerschpacher M, Hartmann J, Huber JC, Schittl H, Quint RM
Jazyk: angličtina
Zdroj: Journal of photochemistry and photobiology. B, Biology [J Photochem Photobiol B] 2010 Jan 21; Vol. 98 (1), pp. 20-4. Date of Electronic Publication: 2009 Oct 20.
DOI: 10.1016/j.jphotobiol.2009.10.003
Abstrakt: 4-Hydroxyestrone (4-OHE(1)), a typical cancer-inducing metabolite, originating from 17beta-estradiol (17beta-E2), was chosen as a model for the studies. The aim was to get a deeper insight in the mechanisms of its ability to initiate cancer. It was found, that 4-OHE(1) can eject electrons (e(aq)(-)), when excited in the singlet state by monochromatic UV-light (lambda=254 nm) in polar media (water:ethanol=40:60 vol.%). The quantum yield Q(e(aq)(-)), determined for various 4-OHE(1) concentrations, is found to be as high as that previously observed for 17beta-E2. It decreases with increasing substrate concentration, but it is enhanced at higher temperature. The ability of 4-OHE(1) to eject as well as to consume and to transfer electrons to other biological systems, classifies it as an electron mediator, similar to 17beta-E2. The 4-OHE(1) transients resulting of the electron emission process are leading to the formation of secondary metabolites. Surprisingly, it was established that the secondary metabolites possess likewise the ability to eject as well as to consume electrons. Hence, they behave similar like 17beta-E2. However, the structure of the secondary formed metabolites, which determinates their biological properties and carcinogenity, depends on the nature of the available reaction partners involved in their formation. A probable reaction mechanism explaining the subject matter is discussed.
(Copyright 2009 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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