Cellular and subcellular localization of nicotinamide adenine dinucleotide phosphate diaphorase activity.
OBJECTIVE
To determine the cellular and subcellular distribution of nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) in the human placenta and thereby to shed light on the possible role of nitric oxide (NO) and NO synthase in this tissue.


METHODS
NADPH-d activity in 10 term placenta and in 10 first-trimester placentas was examined by enzyme histochemistry and by both light microscopy and electron microscopy.


RESULTS
Light microscopy revealed that NADPH-d activity was marked in the syncytiotrophoblasts, moderate in the endothelium of cord vessels, and weak in the amniotic epithelia and chorionic trophoblasts. At the electron-microscopic level, NADPH-d activity was apparent as small patches distributed throughout the cytoplasm of the syncytiotrophoblasts.


CONCLUSIONS
NO might be generated in the syncytiotrophoblast of the human placenta and might play a role in the regulation of placental hemodynamics or in the signaling between the syncytium and the villous mesenchyme.
Matsubara
S
S
Department of Obstetrics and Gynecology, Jichi Medical School, Tochigi, Japan.
Minakami
H
H
Takayama
T
T
Sato
I
I
D000650:Amnion / Q000201:enzymology; D002823:Chorion / Q000201:enzymology; D003593:Cytoplasm / Q000201:enzymology; D004730:Endothelium, Vascular / Q000201:enzymology; D004848:Epithelium / Q000201:enzymology; D005260:Female; D006801:Humans; D008854:Microscopy, Electron; D009252:NADPH Dehydrogenase / Q000032:analysis* / Q000378:metabolism; D015388:Organelles / Q000201:enzymology; D010920:Placenta / Q000098:blood supply / Q000201:enzymology* / Q000648:ultrastructure; D011247:Pregnancy; D014327:Trophoblasts / Q000201:enzymology
D009252:NADPH Dehydrogenase