Loading…
Androgens Modulate Nitric Oxide Synthase Messenger Ribonucleic Acid Expression in Neurons of the Major Pelvic Ganglion in the Rat
Expression and androgen regulation of the gene for neuronal nitric oxide synthase (NOS I) were examined in neurons of the major pelvic ganglia in male rats. Some of these postganglionic neurons innervate the penis and produce nitric oxide, which is believed to play a major role in penile erection. R...
Saved in:
Published in: | Endocrinology (Philadelphia) 1997-08, Vol.138 (8), p.3093-3102 |
---|---|
Main Authors: | , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that cite this one |
Online Access: | Get full text |
Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
Summary: | Expression and androgen regulation of the gene for neuronal nitric
oxide synthase (NOS I) were examined in neurons of the major pelvic
ganglia in male rats. Some of these postganglionic neurons innervate
the penis and produce nitric oxide, which is believed to play a major
role in penile erection. Rats were either castrated or sham operated
and implanted with SILASTIC brand capsules filled with powdered
testosterone (T) or 5α-dihydrotestosterone (5αDHT) or left empty.
After 4 days, the number of neurons intensely stained for
NADPH-diaphorase as well as those giving a NOS I signal in in
situ hybridization experiments increased in castrated rats
treated with testosterone by 31% and 42%, respectively, relative to
those in untreated castrated rats. This suggests that the increase in
NADPH-diaphorase activity resulted from enzyme synthesis and was due to
a modification of NOS I messenger RNA (mRNA) accumulation. After 7
days, Northern blot analysis showed that castration produced a decrease
in the amount of NOS I mRNA relative to that of ribosomal RNA. This
decrease was almost prevented by T treatment. No significant
differences were observed by reverse transcriptase-PCR between 7-day
and 28-day treatments. However, in 7-day castrated rats treated with
5αDHT, NOS I signals relative to those of hypoxanthine
phosphoribosyltransferase, taken as reference, were significantly
higher than those in castrated rats and resembled those in
sham-castrated rats, suggesting that 5αDHT was probably more potent
than testosterone in preventing the decrease in NOS I mRNA levels
elicited by castration. These results show that NOS I can be positively
regulated by androgens and are consistent with the suggestion that
these steroids play a role in the physiological processes of penile
erection. |
---|---|
ISSN: | 0013-7227 1945-7170 |
DOI: | 10.1210/endo.138.8.5310 |