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Increases in serum sphingomyelin by 17β‐estradiol
Author(s) -
Merrill Alfred H.,
Wang Elaine,
Innis Wendy S. A.,
Mullins Richard
Publication year - 1985
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/bf02534197
Subject(s) - sphingomyelin , medicine , endocrinology , enzyme , cholesterol , chemistry , sphingolipid , very low density lipoprotein , estrogen , clinical chemistry , lipidology , lipoprotein , biochemistry , biology
The effects of estrogens on plasma sphingomyelin and the hepatic activity of the initial enzyme of sphingomyelin synthesis were examined using immature chicks. After three days of 17β‐estradiol administration, serum sphingomyelin, total phospholipids, and cholesterol doubled, and triacylglycerol levels increased 7.5 fold. The sphingomyelin content and percentage of total phospholipids of liver were unaffected by estrogen treatment. The specific activity of serine palmitoyltransferase (EC 2.3.1.50) was unchanged, but the total activity appeared slightly higher due to increased liver weights. The higher spingomyelin may, therefore, be due less to increased levels of biosynthetic enzymes than to factors such as the substrate (i.e., fatty acid) supply or decreased clearance of plasma sphingomyelin. These results are similar to earlier findings with key enzymes of cholesterol and glycerolipid biosynthesis and suggest that the three lipid pathways may be coordinated during estrogen treatment and enhanced very‐low density lipoprotein (VLDL) synthesis.