The Levels of Serum Free Amino Acids: L-Glutamine, L-Arginine, L-Citrulline, in Women With Intrauterine Growth Retardation

摘要

Intrauterine growth retardation (IUGR) affects approximately 8% of all pregnancies [1], The pathophysiology of IUGR is multifactorial and poorly understood. However, the reduced growth of the fetus is associated with placental insufficiency manifested as increased uterine vascular resistance and reduced uterine blood flow [2, 3], Placental angiogenesis and blood flow are dependent on the interaction of locally produced angiogenic factors and va-soactive agents [4], Nitric oxide (NO) is known to mediate many physiological and pathological functions, including angiogenesis and vascular permeability. [5, 6, 7] During pregnancy NO is produced primarily by the endothe-lium of both uterine and systemic arteries [8, 9, 10] Nitric oxide synthase (NOS) inhibition have been shown to induce placental and fetal growth restriction [11, 12]. NO and L-citrulline are synthesized from amino acid L-arginine by NO synthase (NOS) [13]. Another amino acid L-glutamine - the most abundant free amino acid in plasma is structurally similar to L-citrulline. In vitro study indicates that glutamine can limit arginine availability for NO production by inhibiting recycling of citrulline to arginine [14, 15].