title: The enigma of continual plasma volume expansion in pregnancy: critical role of the renin-angiotensin-aldosterone system.
abstract: Pregnancy is characterized by avid renal sodium retention and plasma volume expansion in the presence of decreased blood pressure. Decreased maternal blood pressure is a consequence of reduced systemic vascular tone, which results from an increased production of vasodilators [nitric oxide (NO), prostaglandins, and relaxin] and decreased vascular responsiveness to the potent vasoconstrictor (angiotensin II). The kidneys participate in this vasodilatory response, resulting in marked increases in renal plasma flow and glomerular filtration rate (GFR) during pregnancy. In women, sodium retention drives plasma volume expansion (∼40%) and is necessary for perfusion of the growing uterus and fetus. For there to be avid sodium retention in the presence of the potent natriuretic influences of increased NO and elevated GFR, there must be modifications of the tubules to prevent salt wasting. The purpose of this review is to summarize these adaptations.
authors.affiliation: Department of Medicine, Georgetown University, Washington, District of Columbia; caw240@georgetown.edu.
authors.forename: Crystal A
authors.initials: CA
authors.lastname: West
authors.affiliation: Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi; and.
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Sasser
authors.affiliation: Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida.
authors.forename: Chris
authors.initials: C
authors.lastname: Baylis
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology; D006801:Humans; D010953:Plasma Volume / Q000502:physiology*; D011247:Pregnancy; D017595:Renal Plasma Flow / Q000502:physiology*; D012084:Renin-Angiotensin System / Q000502:physiology*
keywords: ENaC; PDE5; RAAS; kidney; nitric oxide