Heme oxygenase expression in selected regions of term human placenta.
Carbon monoxide (CO), formed during heme oxygenase (HO)-catalyzed oxidation of heme, has been proposed to play a complementary role with nitric oxide in the regulation of placental hemodynamics. The objective of this study was to elucidate HO enzymatic activity and HO-1 (inducible) and HO-2 (constitutive) protein content in the microsomal subcellular fraction of homogenate of selected regions of placenta from normotensive and mild pre-eclamptic pregnancies. HO enzymatic activity was measured under optimized conditions by gas chromatography using CO formation as an index of activity, and HO-1 and HO-2 protein content were determined by Western immunoblot analysis. Microsomal HO activity in each of the four placental regions was not different between normotensive and mild pre-eclamptic pregnancies. Microsomal HO-2 protein content was not different between normotensive and mild pre-eclamptic pregnancies, whereas there was increased expression of microsomal HO-1 protein in chorionic villi and fetal membranes from pre-eclamptic pregnancy compared with normotensive pregnancy. Microsomal HO enzymatic activity correlated with HO-2, but not HO-1, protein content.
McLaughlin
Brian E
BE
Departments of Pharmacology, Faculty of Health Sciences, Queen's University, Kingston, Ontario, Canada K7L 3N6.
Lash
Gendie E
GE
Smith
Graeme N
GN
Marks
Gerald S
GS
Nakatsu
Kanji
K
Graham
Charles H
CH
Brien
James F
JF
D002458:Cell Fractionation; D005260:Female; D006419:Heme Oxygenase (Decyclizing) / Q000378:metabolism*; D051547:Heme Oxygenase-1; D006801:Humans; D008565:Membrane Proteins; D008861:Microsomes / Q000201:enzymology; D010920:Placenta / Q000201:enzymology*; D011225:Pre-Eclampsia / Q000378:metabolism*; D011247:Pregnancy
D008565:Membrane Proteins; C496541:HMOX1 protein, human; D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1; C105245:heme oxygenase-2