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Effects of 17β‐estradiol and starvation on trout plasma lipoproteins
Author(s) -
Wallaert Charlotte,
Babin Patrick J.
Publication year - 1992
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/bf02535584
Subject(s) - medicine , endocrinology , vitellogenin , very low density lipoprotein , trout , postprandial , chemistry , lipoprotein , apolipoprotein b , rainbow trout , cholesterol , lipolysis , biology , biochemistry , insulin , adipose tissue , fish <actinopterygii> , fishery , gene
Administering 17β‐estradiol (E 2 ) to juvenile trout results in plasma hyperlipidemia and hyperlipoproteinemia associated with significant increases in the concentrations of triglycerides (TG), free cholesterol, phospholipids, free fatty acids and proteins, both postprandial and during starvation. TG undergo the greatest increase (9 times control level 96 h after feeding). The concentration differences between E 2 ‐treated and control trout increase during starvation, primarily by progressive decreases in the concentrations of various lipids in controls. E 2 ‐induced hypertriglyceridemia is mainly caused by an increase in the concentration of very low density lipoproteins (VLDL) during both the postprandial period (6 times control level at 24 h) and during starvation (15 times control level at 96 h); hyperlipoproteinemia lasts up to at least 7 d after the last feeding. E 2 treatment does not change the concentration of high density lipoproteins, but does increase plasma concentrations of a very high density lipoprotein, vitellogenin (VTG). In E 2 ‐treated VLDL, cholesteryl esters are depleted while proteins are enriched. During the postprandial phase, the apolipoprotein (apo) profile of VLDL (d< 1.015 g/mL) is comparable in E 2 ‐treated and control trout. Starvation of E 2 ‐treated trout is accompanied by an enrichment in apo B 240 , A‐I and A‐II. The secretion levels of TG and VLDL‐TG, as determined in vivo , by injecting Triton WR‐1339 to starving animals, are significantly higher in E 2 ‐treated trout than in controls. In trout, as in chicks, E 2 administration significantly increases the concentration and hepatic secretion of plasma VLDL independent of the nutritional status and the appearance of VTG in the plasma. This suggests the existence of similar mechanisms for the regulation of lipoprotein metabolism by estrogens in oviparous vertebrates.