Immunohistochemical description of nitric oxide synthase isoforms in human clitoris.
OBJECTIVE
Our aim was to identify and localize nitric oxide synthase isoforms in the human clitoris in support of the hypothesis that nitric oxide mediates erectile function in this organ.


METHODS
Nitric oxide synthase immunohistochemistry studies specific for neuronal, inducible and endothelial isoforms of the enzyme were performed on human clitoral tissue obtained from 4 patients (3 with female pseudohermaphroditism and 1 with true hermaphroditism) at feminizing genitoplasty and from 1 phenotypically normal woman at autopsy.


RESULTS
Neuronal nitric oxide synthase immunoreactivity was detected in nerve bundles and fibers coursing within the glans clitoris and corpora cavernosa of the clitoris, predominating in the latter tissue. Specific inducible nitric oxide synthase immunoreactivity was not identified. Endothelial nitric oxide synthase immunoreactivity was detected in vascular and sinusoidal endothelium of these tissues with a predominance in the glans clitoris.


CONCLUSIONS
The presence and anatomical localizations of nitric oxide synthase isoforms in the human clitoris indicate that nitric oxide is generated in this organ. These data suggest that nitric oxide may be involved in the erectile physiology of the clitoris as a modulator of clitoral smooth muscle activity. Functional studies are required to support this hypothesis.
Burnett
A L
AL
Department of Urology, James Buchanan Brady Urological Institute, Johns Hopkins Hospital and School of Medicine, Baltimore, Maryland 21287-2411, USA.
Calvin
D C
DC
Silver
R I
RI
Peppas
D S
DS
Docimo
S G
SG
D002648:Child; D002987:Clitoris / Q000737:chemistry*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D007527:Isoenzymes / Q000032:analysis*; D019001:Nitric Oxide Synthase / Q000032:analysis*
D007527:Isoenzymes; D019001:Nitric Oxide Synthase