Effect of 7,8 -Dihydroneopterin, Biopterin and Isoxanthopterin on Cholesterol and Phospholipid Content and Phospholipid Biosynthesis in Vitro

Abstract

Incorporation of fatty acids into phospholipids has been investigated using samples of rat liver tissue homogenate (Krebs-Ringer-phosphate buffer, pH=7.4, containing 0.3% albumin, fatty acid mixture and glycerol). The addition of 7,8-dihydroneopterin and biopterin (5 and 30 pmol/g wet weight) to incubation medium induced a decrease of palmitic (7,8-dihydroneopterin) and stearic acid (7,8-dihydroneopterin, biopterin) and an increase of linolenic (7,8-dihydroneopterin) and arachidonic acid (7,8 - dihydroneopterin, biopterin) incorporation into phospholipids. Cholesterol content decreased but phospholipid content did not change in samples containing 7,8-dihydroneo-pterin or biopterin. No changes of fatty acid incorporation into phospholipids as well as of the content of cholesterol and phospholipids were observed in samples after addition of isoxanthopterin (5 and 30 pmoljg wet weight) to incubation medium for phospholipid biosynthesis in vitro. Despite the fact that 7,8-dihydroneopterin and biopterin have different oxidation states and some similar effects on phospholipid biosynthesis and cholesterol content have been observed in our study, we suggest that the oxidation state of pteridines is more important than the pterin-( 6 )-side chain in the deviations of fatty acid incorporation into phopholipids as well as in the regulation of cholesterol content in samples

Keywords

• 7,8-dihydroneopterin
• biopterin
• isoxanthopterin
• fatty acids
• phospholipids
• cholesterol