Regulation of oleic acid synthesis in lymphoid cells / by Martha R. Lowe.
| Author/creator | Lowe, Martha R. author. |
| Other author | Buttke, Thomas M., degree supervisor. |
| Other author | East Carolina University. Department of Biology. |
| Format | Theses and dissertations |
| Production | 1992. |
| Description | v, 56 leaves : illustrations ; 28 cm |
| Supplemental Content | Access via ScholarShip |
| Subjects |
| Summary | The regulation of fatty acid synthesis in lymphoid cells was studied in BW5147 cells, a murine T lymphoma cell line. BW5147 cells grown in the absence of fetal calf serum (FCS) or in the presence of low (1%) FCS synthesized both saturated and unsaturated fatty acids in roughly equal proportions, but cells grown in the presence of 10% FCS synthesized predominantly (90%) saturated fatty acids (SFA). Based on gas-liquid chromatographic analyses of cellular phospholipid fatty acids, the suppressive effects of 10% FCS on unsaturated fatty acid (UFA) synthesis could best be correlated with the exogenous supply of arachidonic acid (20:4). To examine this putative relationship in more detail, BW5147 cells cultured in 1% FCS medium were additionally supplemented with varying doses of oleic acid (18:1), linoleic acid (18:2) or 20:4. The cells were subsequently analyzed for both their membrane fatty acid content as well as ^ novo UFA synthesis. Supplementation with 18:1 led to little or no change in either parameter but exposure to either 18:2 or 20:4 resulted in reduced levels of UFA synthesis. An excellent correlation was observed between membrane fatty acid composition and endogenous UFA synthesis; increased unsaturation of membrane fatty acids was accompanied by decreased levels of UFA synthesis. Additional studies were done to identify the molecular basis for the suppression of UFA synthesis by 20:4. Microsomal membranes isolated from BW5147 cells cultured in the presence and absence of 20:4 were assayed for their levels of stearyl-CoA desaturase (SCD), the enzyme which desaturates steric acid to form oleic acid. SCD levels in 20:4-treated cells were found to be decreased by 65-70% compared to untreated cells, in good agreement with the results obtained with intact cells. Furthermore, Northern blot analyses on either total or poly-A+ cellular RNA from BW5147 cells grown in the presence of 20:4 displayed reduced levels of SCD mRNA compared to untreated control cells. Collectively, the data indicate that 20:4 regulates fatty acid synthesis in lymphoid cells by modulating the levels of SCD protein. It is proposed that the primary regulation occurs at the level of transcription of SCD. |
| General note | Submitted to the faculty of the Department of Biology. |
| General note | Advisor: Thomas M. Buttke |
| Dissertation note | M.S. East Carolina University 1992 |
| Bibliography note | Includes bibliographical references (leaves 54-55). |
| Genre/form | Academic theses. |
| Genre/form | Academic theses. |
| Genre/form | Thèses et écrits académiques. |