Uptake and utilization of lipoprotein cholesteryl esters by rat granulosa cells
| Autor: | Louisa Tsai, Salman Azhar, Eve Reaven |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
medicine.medical_specialty
Lipoproteins Sterol O-acyltransferase Biophysics Tyramine Biology Biochemistry Iodine Radioisotopes chemistry.chemical_compound Endocrinology Internal medicine Cholesterylester transfer protein polycyclic compounds medicine Animals Cells Cultured Intermediate-density lipoprotein Granulosa Cells Cholesterol Lipoproteins HDL3 Rats Inbred Strains Endocytosis Rats Lipoproteins LDL Microscopy Electron Bucladesine chemistry Cell culture Cholesteryl ester biology.protein Female lipids (amino acids peptides and proteins) Cholesterol Esters Lipoproteins HDL Intracellular Lipoprotein |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism. 1047:148-160 |
| ISSN: | 0005-2760 |
| DOI: | 10.1016/0005-2760(90)90041-u |
| Popis: | Earlier studies have shown that rat granulosa cells grown in serum-free medium are exquisitely responsive to exogenously provided lipoprotein cholesterol. In this study we compare the amount of cholesterol (cholesteryl ester) actually delivered from various homologous and heterologous cholesterol-rich lipoproteins and examine the intracellular pathways used in the delivery system. Granulosa cells were incubated for 5 or 24 h with 125I-labeled human (h) HDL3, rat (r) HDL or hLDL equipped with non-releasable apoprotein and cholesteryl ether tags which accumulate within cells, even after degradation. We show that all the tested lipoproteins were similarly efficient in cholesteryl ester delivery; i.e., based on cholesterol: protein ratios of the starting ligands, each delivered approximately the same cholesteryl ester mass and evoked a similar progestin response. However, each lipoprotein was processed quite differently by the granulosa cells: hHDL3-cholesteryl ester was taken up almost exclusively by an non-endocytic pathway, hLDL-cholesteryl ester almost exclusively by an endocytic pathway and rHDL-cholesteryl ester by both pathways. In general, there was no correlation between the total amount of lipoprotein bound or apoprotein internalized and/or degraded by the cells with the amount of cholesteryl ester received or the level of the progestin response. Hormone stimulation upregulated the preferred pathway for each lipoprotein. |
| Databáze: | OpenAIRE |
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