Vascular angiotensin II and atrial natriuretic peptide receptors in normal and growth-retarded human placentae.
Receptors for angiotensin II (AII) and atrial natriuretic peptide (ANP) were characterized in a membrane fraction from resistance-type artery from human placentae. Placentae from normal pregnancies and pregnancies complicated by intrauterine growth retardation (IUGR) were studied. High- and low-affinity receptors for AII (dissociation equilibrium constant (Kd) 1.7 and 15.7 nmol/l respectively) and ANP (Kd 0.2 and 55.5 nmol/l respectively) were identified; these parameters were unchanged in IUGR, but there was a reduction in high-affinity receptor number by approximately 50% for AII and 80% for ANP in this condition. Both peptides may have a role in the regulation of fetoplacental blood flow. The alterations in IUGR are consistent with sustained activation of the fetal renin-angiotensin system and suggest altered vascular responsiveness to ANP.
McQueen
J
J
Medical Research Council Blood Pressure Unit, Western Infirmary, Glasgow.
Kingdom
J C
JC
Jardine
A G
AG
Connell
J M
JM
Whittle
M J
MJ
D000804:Angiotensin II / Q000378:metabolism*; D001158:Arteries / Q000032:analysis; D009320:Atrial Natriuretic Factor / Q000378:metabolism*; D005260:Female; D005317:Fetal Growth Retardation / Q000378:metabolism*; D006801:Humans; D010920:Placenta / Q000032:analysis*; D011247:Pregnancy; D011869:Radioligand Assay; D011945:Receptors, Angiotensin / Q000032:analysis*; D017461:Receptors, Atrial Natriuretic Factor; D011956:Receptors, Cell Surface / Q000032:analysis*
D011945:Receptors, Angiotensin; D011956:Receptors, Cell Surface; D000804:Angiotensin II; D009320:Atrial Natriuretic Factor; D017461:Receptors, Atrial Natriuretic Factor