Effects of glycyl-histidyl-lysine on Morris hepatoma 7777 cells.
Glycyl-histidyl-lysine (GHL) has been shown to have growth stimulatory effects on a number of different cell types including hepatocytes and hepatoma cells. In this study, the effects of GHL on Morris hepatoma 7777 cells were investigated. The greatest stimulatory effects on 3H-thymidine and 3H-leucine incorporation were observed at a GHL concentration of 2 ng/ml. In randomly proliferating cells, the incorporation of 3H-thymidine into DNA increased by 50% and that of 3H-leucine into protein by 29%. In addition, synergistic effects were observed when insulin and glucagon were included with GHL in the incubation mixture. Experiments with cells rendered quiescent by serum starvation indicated that cells in the G1 phase of the cell cycle are more sensitive to GHL stimulation. In these experiments, 3H-thymidine incorporation increased earlier and peaked at a higher value than in the control cells. This finding suggests that GHL may play a role in stimulating quiescent cells to re-enter the cell cycle.
Barra
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Department of Biological Sciences, Mary Washington College, Fredericksburg, Virginia 22401.
D000818:Animals; D002453:Cell Cycle / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects*; D002460:Cell Line; D004273:DNA, Neoplasm / Q000096:biosynthesis; D003907:Dexamethasone / Q000494:pharmacology; D005934:Glucagon / Q000494:pharmacology; D006133:Growth Substances / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology; D008114:Liver Neoplasms, Experimental / Q000378:metabolism / Q000473:pathology*; D009363:Neoplasm Proteins / Q000096:biosynthesis; D009842:Oligopeptides / Q000494:pharmacology*
D004273:DNA, Neoplasm; D006133:Growth Substances; D007328:Insulin; D009363:Neoplasm Proteins; D009842:Oligopeptides; C020905:glycyl-histidyl-lysine; D003907:Dexamethasone; D005934:Glucagon