The Library
Rapid effects of 17β-estradiol on hepatocytes
Tools
Stratton, Rebecca Claire (2008) Rapid effects of 17β-estradiol on hepatocytes. PhD thesis, University of Warwick.
Research output not available from this repository.
Request-a-Copy directly from author or use local Library Get it For Me service.
Official URL: http://webcat.warwick.ac.uk/record=b2334550~S15
Abstract
17β-estradiol is the most potent circulating estrogenic hormone. The classical mode of action of 17β-estradiol involves its translocation to the nucleus and regulation of transcription. However, numerous rapid, non-genomic actions of 17β-estradiol have been demonstrated in several cell types. This thesis demonstrates that 17β-estradiol rapidly elevates hepatocyte cGMP and stimulates plasma membrane Ca2+ efflux. In contrast, 17α-estradiol, an optical isomer, is without effect on cGMP or Ca2+ efflux. The Ca2+ efflux stimulation is protein kinase G (PKG)-dependent. This thesis also demonstrates the expression of PKG isoforms Iα and Iβ in hepatocytes, and that 17β-estradiol rapidly recruits PKGIα to the hepatocyte plasma membrane.
The observed effects of 17β-estradiol are mimicked by 17β-estradiol rendered membrane-impermeant by linkage to BSA. Moreover, 17β-estradiol binding at the hepatocyte plasma membrane was directly visualised using fluoroscein-labelled 17β-estradiol-BSA. The nature of the plasma membrane receptor involved was found to have a similar pharmacological profile to the ‘γ-adrenergic receptor’.
17β-estradiol protects both liver and isolated hepatocytes under pathophysiological conditions that have been associated with a rise in intracellular Ca2+ concentration ([Ca2+]i). Hepatoprotection by 17β-estradiol has previously been attributed to its antioxidant properties. A rise in [Ca2+]i is a common early event in cell injury, activating many Ca2+-dependent enzymes including calpain. Single cell Ca2+ measurements showed that 17β-estradiol attenuates both the amplitude and duration of ATP-induced [Ca2+]i rises. 17β-estradiol protects hepatocytes against the [Ca2+]i-dependent elevation of calpain activity and the decline in cell viability induced by both ATP and the bile acid taurolithocholate. The effects of 17β-estradiol on [Ca2+]i, calpain activity and cell viability are dependent on PKG. I propose that 17β-estradiol stimulates plasma membrane Ca2+ efflux through elevation of cGMP and subsequent activation and recruitment of PKGIα to the plasma membrane; this is a potential mechanism through which 17β-estradiol protects hepatocytes by alleviating harmful [Ca2+]i rises.
Item Type: | Thesis (PhD) | ||||
---|---|---|---|---|---|
Subjects: | Q Science > QH Natural history > QH301 Biology | ||||
Library of Congress Subject Headings (LCSH): | Liver cells -- Research, Estradiol, Transcription factors -- Research | ||||
Official Date: | September 2008 | ||||
Dates: |
|
||||
Institution: | University of Warwick | ||||
Theses Department: | Department of Biological Sciences | ||||
Thesis Type: | PhD | ||||
Publication Status: | Unpublished | ||||
Supervisor(s)/Advisor: | Green, Anne K. | ||||
Sponsors: | Biotechnology and Biological Sciences Research Council (Great Britain) (BBSRC) | ||||
Extent: | 1 v. (various pagings) : ill., charts | ||||
Language: | eng |
Request changes or add full text files to a record
Repository staff actions (login required)
View Item |