|Thame, Minerva -|
|Fletcher, Horace -|
|Baker, Tameka -|
|Marini, Juan -|
|Kao, Christina -|
|Jahoor, Farook -|
Submitted to: Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 21, 2010
Publication Date: November 17, 2010
Citation: Thame, M.M., Fletcher, H.M., Baker, T.M., Marini, J.C., Kao, C.C., Jahoor, F. 2010. Arginine flux, but not nitric oxide synthesis, decreases in adolescent girls compared with adult women during pregnancy. Journal of Nutrition. 141:71-74. Interpretive Summary: Arginine is an amino acid that has many functions; among those is the precursor for nitric oxide (NO), a molecule involved in the regulation of blood pressure. Pregnancy-induced hypertension is a serious condition and is more prevalent in adolescents than in adult women. Here we show that the pregnant adolescent cannot maintain arginine production like her adult counterpart in late pregnancy. However, it does not affect their ability to synthesize NO in late pregnancy.
Technical Abstract: Nitric Oxide (NO) has been proposed as a mediator of vascular expansion during pregnancy. Inability to increase NO synthesis and/or production of its precursor, arginine, may contribute to pregnancy-induced hypertension. Adolescents have a higher incidence of gestational hypertension. It is not known whether pregnant adolescents can produce sufficient arginine to meet overall demands. Our objective was to measure and compare the arginine flux and NO synthesis rates of pregnant adolescents and adult women. Arginine, citrulline, and NO kinetics were measured by i.v. infusions of (15) N (2)-argininine and (2) H (2)-citrulline in 8 adolescents and 8 adult women in the fasted state at the end of the first and the beginning of the 3rd trimesters of pregnancy. Arginine flux decreased (P < 0.05) from trimester 1 to 3 in the adolescents but not in the adult women. NO synthesis rate did not change significantly in either group from trimester 1 to 3. In trimester 3, there was a positive association (r = 0.55; P = 0.02) between arginine flux and participants' age, indicating that flux was slower in the younger participants. These findings suggest that after a brief period of food deprivation, the pregnant adolescent cannot maintain arginine production like her adult counterpart in late pregnancy. This inability to maintain arginine production seems to be related to her younger age. It does not, however, affect her ability to synthesize NO in late pregnancy.