The divergent metabolic fate of ether analogs of cholesteryl and retinyl esters after injection in lymph chylomicrons into rats
| Autor: | Gideon Halperin, DeW.S. Goodman, Olga Stein, Yechezkiel Stein |
|---|---|
| Rok vydání: | 1983 |
| Předmět: |
Biophysics
Spleen Ether Tritium Biochemistry Exocytosis Excretion chemistry.chemical_compound Endocrinology Retinyl palmitate Chylomicrons Cholesterylester transfer protein medicine Animals Carbon Radioisotopes Vitamin A biology Rats Kinetics Cholesterol medicine.anatomical_structure Liver chemistry biology.protein lipids (amino acids peptides and proteins) Lymph Lipoproteins HDL Chylomicron |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism. 750:223-230 |
| ISSN: | 0005-2760 |
| DOI: | 10.1016/0005-2760(83)90022-x |
| Popis: | Rat lymph chylomicrons were labeled with ether analogs of cholesteryl linoleate and retinyl palmitate and injected into rats. Labeling was achieved by transfer of [14C]cholesteryl linoleyl ether and retinyl [3H]hexadecyl ether from partially delipidated HDL to chylomicrons. Transfer was effected by the use of d > 1.25 g/ml fraction of human serum as a source of cholesteryl ester transfer protein activity. Less effective transfer of retinyl ether than of cholesteryl ether was observed. 3 h after injection 85–90% of the 14C and 80–85% of the 3H were recovered in the liver. Thereafter, the cholesteryl and retinyl ethers were lost progressively from the liver at very slow but differing rates. After 4 days, two-thirds of the [14C]cholesteryl ether but only one-third of the 3H-labeled retinyl ether were found in the liver. By 27 days, the hepatic recovery of 14C had decreased to 20–25%, and that of 3H to about 3% of the injected dose. In contrast, the amount of [14C]cholesteryl linoleyl ether recovered in the spleen did not change during 27 days, while the 3H label in the spleen declined about 10-fold. There was no redistribution of either labeled compound from the liver to extrahepatic tissues, indicating that the labeled compounds were lost from the body, most probably through the bile. More than 90% of the 14C recovered in liver was in nonsaponifiable form up to almost 2 weeks after injection. The data suggest that elimination of the labeled compounds occurred without prior hydrolysis of the ether bond. In addition, the finding that the two lipid ether analogs were eliminated from the liver at very different rates suggests that excretion into bile may have occurred not by exocytosis of whole lysosomal contents, but rather by differential diffusion of the two lipids through the lysosomal membrane. |
| Databáze: | OpenAIRE |
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