Effect of 25-hydroxycholesterol and bile acids on the regulation of cholesterol metabolism in Hep G2 cells
| Autor: | B A Kottke, T L Carlson |
|---|---|
| Rok vydání: | 1989 |
| Předmět: |
Apolipoprotein E
medicine.medical_specialty Apolipoprotein B medicine.drug_class In Vitro Techniques Chenodeoxycholic Acid Biochemistry chemistry.chemical_compound Apolipoproteins E Internal medicine Tumor Cells Cultured medicine Humans Secretion Lovastatin RNA Messenger Molecular Biology Apolipoproteins A Triglycerides Apolipoprotein A-I biology Bile acid Cholesterol Cell Biology Metabolism Hydroxycholesterols Lipoproteins LDL Hep G2 Endocrinology Liver Receptors LDL chemistry LDL receptor biology.protein lipids (amino acids peptides and proteins) Research Article |
| Zdroj: | Biochemical Journal. 264:241-247 |
| ISSN: | 1470-8728 0264-6021 |
| Popis: | The effect of 25-hydroxycholesterol (25-OH-cholesterol) and chenodeoxycholic (CDC) acid on apoprotein secretion, low-density lipoprotein receptor activity, and [3H]triacylglycerol secretion in Hep G2 cells was studied. Both 25-OH-cholesterol and CDC acid increased the secretion of apolipoprotein (apo) E by Hep G2 cells. The secretion of apo A-I was slightly lowered (less than 10% disease). The maximal increase in apo E secretion was observed in culture medium containing 2 micrograms of 25-OH-cholesterol/ml or 10 micrograms of CDC acid/ml plus 10% fetal calf serum. Cholesterol, 7-OH-cholesterol and other bile acids were ineffective in inducing increases in apo E secretion. Another cholesterol synthesis inhibitor, mevinolin, was also ineffective in generating an increase in apoprotein secretion. The data indicated a specific interaction between 25-OH-cholesterol or CDC acid and apo E secretion in Hep G2 cells. Cholesterol synthesis, as measured by the incorporation of [14C]acetic acid into sterols, was repressed in Hep G2 cells in the presence of 25-OH-cholesterol (17% of control value). CDC acid, on the other hand, increased [14C]acetic acid incorporation (156% of control value). The number of LDL receptors in Hep G2 cells was decreased after incubation with 25-OH-cholesterol (62% of control value), but increased significantly after incubation with CDC acid (149% of control value). The secretion of [3H]triacylglycerol by Hep G2 cells incubated with 25-OH-cholesterol was greatly increased (248% of control value). On the contrary, CDC acid did not cause any increase in [3H]triacylglycerol secretion. The above results suggest that 25-OH-cholesterol and CDC acid have different effects on lipid metabolism in Hep G2 cells. The mRNA levels of apo E increased in cells preincubated with 25-OH-cholesterol and CDC acid, which suggested that the increase in apo E secretion is at least partly due to an increase in synthesis. |
| Databáze: | OpenAIRE |
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