Effects of Ethanol on Growth and Cyclic AMP in Cultured Cells

Sweeney, Anne M (1976) Effects of Ethanol on Growth and Cyclic AMP in Cultured Cells. MSc(R) thesis, University of Glasgow.

Abstract

Studies on the effects of ethanol on the body have so far failed to identify any direct mechanism of action that may account for the typical pattern of alcohol intoxication in vivo. The ethanol molecule is capable of reaching the cell membrane of any cell in the body and is known to cause ionic and physical alterations in membrane structure in vivo. The intracellular molecule adenosine 3',5'-cyclic monophosphate (cyclic AMP) has a postulated role as a mediator of hormone action. The formation of cyclic AMP inside the cell is catalysed by the enzyme adenyl cyclase, which is positioned on the cell membrane. It has been suggested that some of the in vivo effects of ethanol may be related to cyclic AMP metabolism. To investigate the action of ethanol at the cellular level, the growth pattern of cultured cells was examined in the presence of ethanol. Concentrations of ethanol were similar to those found in the blood stream of patients admitted intoxicated to the Western Infirmary. L929 cells, a cultured cell line originally derived from mouse fibroblasts, were used. They were regarded as a feasible model for study of intracellular cyclic AMP changes since any such changes are likely to be reflected by alterations in the growth rate of the cells. Growth parameters including cell population density, DNA, RNA and protein were monitored also. Measurement of intracellular cyclic AMP involved establishing an adequate protein binding assay. The validity of the assay was confirmed in terms of quantitative values for assay specificity, accuracy, precision and sensitivity. Ethanol treatment was found to delay cell division probably by temporarily preventing entry into the S phase of the cell cycle. This event was parallelled by higher cell cyclic AMP in ethanol treated cells. Experimental cells tended to be poor in content of DNA and RNA; protein results implied a relationship between cell protein, cell cyclic AMP and growth rate. The evidence suggested that elevated cell cyclic AMP was a critical, though not necessarily primary event related to decreased growth, and could have been a response to decreased availability to the cell of crucial nutrients. After approximately 24 hours delay, ethanol treated cells grew normally in a logarithmic fashion. That the cyclic AMP molecule may have played a role in this compensatory mechanism, is discussed. It is suggested that the same molecular mechanisms may be involved in vivo. Further experiments are suggested to examine the specificity of the alcohol interference and to verify the presence of a compensatory mechanism involving enzyme induction.

• Item Type: Thesis (MSc(R))
• Qualification Level: Masters
• Keywords: Physiology, Cellular biology
• Date of Award: 1976
• Depositing User: Enlighten Team
• Unique ID: glathesis:1976-78745
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 30 Jan 2020 14:57
• Last Modified: 30 Jan 2020 14:57
• URI: https://theses.gla.ac.uk/id/eprint/78745