title: Potential function of amniotic fluid in fetal development---novel insights by comparing the composition of human amniotic fluid with umbilical cord and maternal serum at mid and late gestation.
abstract: BACKGROUND
  Amniotic fluid (AF) is a dynamic and complex mixture. Up to now, little is known about the physiological functions of AF in the process of fetal development. We suppose that AF carries components such as proteins or peptides, which contribute to the regulation of fetal development.
  
  
  METHODS
  Compositions including biochemical components and tumor markers were determined in human AF, umbilical cord serum (UCS) and maternal serum (MS) from the same subject in the range of 15-42 weeks of gestation.
  
  
  RESULTS
  (1) The levels of primary electrolytes such as sodium, chloride, anion gap and osmotic pressure in AF was almost the same as in UCS and MS. (2) The levels of organic substances, including total protein, glucose, triglycerides, cholesterol and various enzymes, were markedly lower in AF than in UCS and MS, especially for total protein, which was 8- and 12.5-fold lower in AF than in UCS and MS, respectively. (3) The levels of tumor markers, including carcinoembryonic antigen, ferritin, cancer antigen 125 and 199, and alpha-fetoprotein in AF displayed different dynamic changes compared to UCS and MS as gestation advanced.
  
  
  CONCLUSIONS
  This study demonstrated that AF is not a result of simple filtration from the blood but an independent fluid. We speculate that proteins or peptides in the amniotic fluid modulate the process of fetus development since they possess potent bioactivity on cellular growth and proliferation. AF provides a pathway to transport these "regulators" to the fetus and thus plays a pivotal role in fetal development.
authors: Hebei Xinglong Institute of Pharmacological and Medical Sciences, Shijiazhuang, China. xinglongtong@hotmail.com
authors: Xing-Long
authors: XL
authors: Tong
authors: Ling
authors: L
authors: Wang
authors: Tan-Bing
authors: TB
authors: Gao
authors: Yu-Guo
authors: YG
authors: Qin
authors: Yu-Qiao
authors: YQ
authors: Qi
authors: Yan-Ping
authors: YP
authors: Xu
mesh_terms: D000328:Adult; D000653:Amniotic Fluid / Q000737:chemistry / Q000502:physiology*; D014408:Biomarkers, Tumor / Q000032:analysis; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D047109:Fetal Development; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy / Q000097:blood*
chemical_list: D014408:Biomarkers, Tumor