Insulin-Mediated Inhibition of Tyrosinase Activity and Protein Synthesis in Melanoma Cell Cultures
| dc.creator | Ehlers, Susan Elizabeth | |
| dc.date.accessioned | 2016-11-14T23:16:20Z | |
| dc.date.available | 2011-02-18T20:35:28Z | |
| dc.date.available | 2016-11-14T23:16:20Z | |
| dc.date.issued | 1984-05 | |
| dc.description.abstract | Insulin lowers basal levels of tyrosinase activity and inhibits the MSH-stimulated rise in tyrosinase in Cloudman S-91 mouse melanoma cell cultures. These cultures are very sensitive to insulin. A concentration of insulin as low as 5 x 10 M insulin produces optimum inhibition. At maximum inhibition, tyrosinase activity is reduced to approximately 50% of control levels. Insulin inhibits cellular proliferation in melanoma cells; however, inhibition of tyrosinase activity precedes this effect. Insulin also inhibits the (Bu)2 cAMP and theophylline stimulated rise in enzyme activity. This finding suggests that insulin exerts its effects at a site distal to cAMP production. Insulin, in fact, does not lower cAMP levels in melanoma cells, nor does it alter the MSH-stimulated rise of cAMP. The inhibitory effect of insulin on tyrosinase activity could not be mimicked by either (Bu)2 cGMP or 8-bromo-cGMP, suggesting that insulin does not exert its effects by altering cellular levels of this nucleotide. Insulin decreases the incorporation of [3H]-leucine into trichloracetic acid insoluble material by 50%, an inhibition which corresponds well with the observed level of reduction of tyrosinase activity. This finding suggests that the inhibition of tyrosinase activity may be caused by a general reduction in protein synthesis due to insulin treatment. | |
| dc.format.mimetype | application/pdf | |
| dc.identifier.uri | http://hdl.handle.net/2346/14235 | en_US |
| dc.language.iso | eng | |
| dc.publisher | Texas Tech University | en_US |
| dc.rights.availability | Unrestricted. | |
| dc.subject | Proteins -- Synthesis | en_US |
| dc.subject | Melanoma | en_US |
| dc.subject | Insulin | en_US |
| dc.subject | Phenol oxidase | en_US |
| dc.subject | Enzyme inhibitors | en_US |
| dc.subject | Rats -- Physiology | en_US |
| dc.title | Insulin-Mediated Inhibition of Tyrosinase Activity and Protein Synthesis in Melanoma Cell Cultures | |
| dc.type | Thesis |