Inhibitory effect of gastrin peptides on triacylglycerol secretion in Hep G2 cells.

Abstract

To determine whether human liver cells respond to gastrin peptides by reducing their secretion of triacylglycerols, as recently observed in rat hepatocytes. Cells of the human hepatoblastoma cell line Hep G2 were incubated with pentagastrin and heptadeca gastrin, followed by lipid analysis of media and cells. Cultivation of cells; analyses of triacylglycerols, cholesterol and protein; statistical analysis. As the secretion of triacylglycerols in Hep G2 cells incubated with basal medium (Eagle's minimum essential medium with non-essential amino acids, penicillin, streptomycin and glutamine) is only about 20% of the triacylglycerol secretion reported for human liver cells, the possibility of detecting statistically significant effects of gastrin peptides on lipid secretion is reduced compared to the situation in normal hepatocytes. However, by a combined addition of 0.1 mmol/l albumin-bound oleate, 10 mmol/l sodium butyrate and 0.1 mg/ml dextran sulphate to the basal medium, the triacylglycerol secretion in Hep G2 cells was found to be more than twice as high as in cells incubated with basal medium alone. With this supplemented medium a biphasic concentration-dependent statistically significant inhibitory effect of both pentagastrin and heptadeca gastrin on triacylglycerol secretion in Hep G2 cells was demonstrated. These results indicate that gastrin peptides may play a role in the regulation of lipoprotein secretion in human liver cells.