Detection of adrenomedullin, a hypotensive peptide, in amniotic fluid and fetal membranes.
OBJECTIVE
Our purpose was to determine whether adrenomedullin, a multifunctional regulatory peptide involved in blood flow regulation and growth stimulation and with antimicrobial activity, was a component of amniotic fluid from second-trimester human fetus and to determine the source of this peptide.


METHODS
A prospective descriptive study was performed on 134 patients undergoing amniocentesis after genetic counseling, ultrasonography, and informed consent. Adrenomedullin expression was determined by immunocytochemical analysis, Western blot analysis, reverse transcriptase-polymerase chain reaction, and in situ reverse transcriptase-polymerase chain reaction in fetal membranes and with radioimmunoassay in amniotic fluids.


RESULTS
Radioimmunoassay of the 134 amniotic fluid specimens revealed adrenomedullin-like immunoreactivity in all of them, ranging in concentration from 10 to 300 fmol/25 microliters (170 +/- 62 fmol/25 microliters). Immunocytochemical analysis, Western blot analysis, reverse transcriptase-polymerase chain reaction, and in situ reverse transcriptase-polymerase chain reaction further established the expression of adrenomedullin protein and messenger ribonucleic acid in fetal amniotic membranes, suggesting that this organ is the source of amniotic adrenomedullin.


CONCLUSIONS
Our results clearly demonstrate the presence of adrenomedullin in second-trimester human amniotic fluid and adrenomedullin messenger ribonucleic acid and protein in amniotic membranes, suggesting that adrenomedullin is a hormone involved in the maintenance of normal pregnancy. Further studies with these molecular tools are in progress to determine the precise role of this hormone and whether adrenomedullin plays a role in the pathogenesis of various disorders of pregnancy.
Macri
C J
CJ
Department of Obstetrics and Gynecology, Uniformed Services University of Health Sciences, Bethesda, MD 20814-4799, USA.
Martínez
A
A
Moody
T W
TW
Gray
K D
KD
Miller
M J
MJ
Gallagher
M
M
Cuttitta
F
F
D053607:Adrenomedullin; D000328:Adult; D000653:Amniotic Fluid / Q000378:metabolism*; D000959:Antihypertensive Agents / Q000378:metabolism*; D015153:Blotting, Western; D005321:Extraembryonic Membranes / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D010455:Peptides / Q000235:genetics / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011446:Prospective Studies; D012333:RNA, Messenger / Q000378:metabolism; D011863:Radioimmunoassay; D014158:Transcription, Genetic
D000959:Antihypertensive Agents; D010455:Peptides; D012333:RNA, Messenger; D053607:Adrenomedullin