MECHANISMS OF HEPATIC PHOSPHATIDYLCHOLINE SYNTHESIS IN ADULT-RAT - EFFECTS OF PREGNANCY

被引:63
作者
BURDGE, GC [1 ]
HUNT, AN [1 ]
POSTLE, AD [1 ]
机构
[1] UNIV SOUTHAMPTON,SOUTHAMPTON,HANTS,ENGLAND
关键词
D O I
10.1042/bj3030941
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Late pregnancy in the rat (gestational ages 16-21 days) was accompanied by a specific increase in hepatic phosphatidylcholine (PC) and phosphatidylethanolamine (PE) molecular species containing C-16:0 at the sn-1 position and polyunsaturated essential fatty acids (PUFA), in particular C-22:6(n-3), at the sn-2 position. Incorporation of either CDP:[Me-C-14]choline or CDP: [1,2-C-14]ethanolamine into hepatic microsomal sn-1 C-16:0 PC or PE molecular species in vitro was greater at term than in nonpregnant animals, suggesting modifications to the composition of specific diacylglycerol (DAG) pools destined for synthesis of either PC or PE. Also, incorporation of [Me-C-14]choline or [Me(14)C]methionine into hepatic PC in vivo over 6 h in term pregnant rats was consistent with decreased phospholipase A(1)-dependent acyl remodelling of sn-1 C-16:0 to sn-1 C-18:0 molecular species. There was, however, no evidence to support any change to the specificity of acyl remodelling. The rate of PC synthesis by the de novo pathway in vivo was increased in term liver compared with non-pregnant animals, accompanied by increased cholinephosphotransferase activity in vitro in d21 liver microsomes. The rate of PC synthesis by PE N-methylation did not appear to change during pregnancy. Changes in composition of plasma PC species at term reflected those of newly synthesized hepatic PC. Our data suggest supply of PUFA to the developing fetal rat is the result of specific adaptations to maternal hepatic phospholipid biosynthesis rather than passive transfer from the maternal diet.
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页码:941 / 947
页数:7
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