title: Determination of asymmetric dimethylarginine, an endogenous nitric oxide synthase inhibitor, in umbilical blood.
abstract: Endothelial cells produce nitric oxide (NO), a potent vasodilator. Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of NO synthase. Little is known about the potential physiological roles of ADMA in a perinatal setting. This study measures concentrations of ADMA in umbilical blood using enzyme-linked immunosorbent assay and those of NO as nitrite/nitrate (NOx(-)) using the Griess assay. Their relationship to the degree of prematurity and maternal clinical condition is examined. Results show that ADMA concentrations in umbilical blood from control newborns were about twice as high as those of lactating women, healthy children, and healthy adults. Umbilical blood NOx(-) concentrations from control newborns were about half of those of lactating women, healthy children, and healthy adults. Consequently, the levels of ADMA relative to NOx(-) were about 4-fold higher in umbilical blood from control newborns than in blood from lactating women, healthy children, and healthy adults. Furthermore, the umbilical blood ADMA concentrations and the ratios of ADMA to NOx(-) in newborns were higher according to their birth prematurity and lower birth weight. The umbilical ADMA concentrations were independent of the delivery mode and maternal preeclampsia. We infer that the high ADMA levels play physiological roles in maintaining vascular tone and blood redistribution to vital organs during birth, thereby favoring the circulatory transition from fetal to neonatal life.
authors.affiliation: Department of Pediatrics, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan. htsuka@fmsrsa.fukui-med.ac.jp
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Tsukahara
authors.forename: Naoko
authors.initials: N
authors.lastname: Ohta
authors.forename: Shuko
authors.initials: S
authors.lastname: Tokuriki
authors.forename: Koji
authors.initials: K
authors.lastname: Nishijima
authors.forename: Fumikazu
authors.initials: F
authors.lastname: Kotsuji
authors.forename: Hisako
authors.initials: H
authors.lastname: Kawakami
authors.forename: Norihito
authors.initials: N
authors.lastname: Ohta
authors.forename: Kyouichi
authors.initials: K
authors.lastname: Sekine
authors.forename: Hironori
authors.initials: H
authors.lastname: Nagasaka
authors.forename: Mitsufumi
authors.initials: M
authors.lastname: Mayumi
mesh_terms: D000293:Adolescent; D000328:Adult; D001120:Arginine / Q000031:analogs & derivatives* / Q000097:blood; D002648:Child; D002675:Child, Preschool; D004791:Enzyme Inhibitors / Q000097:blood*; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009566:Nitrates / Q000097:blood; D052250:Nitric Oxide Synthase Type III / Q000037:antagonists & inhibitors*; D009573:Nitrites / Q000097:blood; D011247:Pregnancy; D014471:Umbilical Veins
chemical_list: D004791:Enzyme Inhibitors; D009566:Nitrates; D009573:Nitrites; C018524:N,N-dimethylarginine; D001120:Arginine; D052250:Nitric Oxide Synthase Type III