This study reports that “arginase is an
indirect regulator of penile and vaginal blood flow and specific arginase
inhibitors may improve genital blood flow during sexual arousal.”
Role of arginase in the male and female sexual arousal
response.
N.N. Kim, D.W. Christianson, and A.M. Traish,
Department of Urology and Institute for Sexual Medicine, Boston University
School of Medicine, Boston, MA 02118, USA,
J Nutr. 2004 Oct;134(10 Suppl):2873S-2879S; discussion 2895S
The NO-cGMP pathway plays a key role in the male and
female genital sexual arousal response. Nitric oxide synthase (NOS) utilizes
L-arginine and oxygen as substrates to produce nitric oxide (NO) and
citrulline. Arginase is a metalloenzyme that catalyzes the hydrolysis of L-arginine
to produce L-ornithine and urea. It is proposed that arginase competes for
L-arginine and reduces NOS activity in genital tissues, thus modulating
sexual function. Using 2 transition state analogue inhibitors of arginase,
2(S)-Amino-6-boronohexanoic acid (ABH) and S-(2-boronoethyl)-L-cysteine (BEC),
we have characterized arginase activity in penile and vaginal tissue.
Neither of these inhibitors has activity against NOS. Thus, ABH and BEC are
useful compounds for examining the role of arginase in genital tissue
physiology, without directly influencing NOS activity. We present data to
suggest that arginase may regulate NO production by competing for endogenous
pools of L-arginine. In this fashion, arginase is an indirect regulator of
penile and vaginal blood flow and specific arginase inhibitors may improve
genital blood flow during sexual arousal. As evidenced by the upregulation
of arginase in specific disease states, its distribution in the vagina, and
its modulation by sex steroid hormones, this enzyme may also participate in
numerous other physiological and pathophysiological processes, such as
tissue growth, fibrosis, and immune function.
PMID: 15465804 [PubMed - indexed for MEDLINE
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