L-arginine, the substrate of nitric oxide synthase, inhibits fertility of male rats.
OBJECTIVE
To examine the effect of L-arginine, the substrate of nitric oxide (NO) synthase, on reproductive function of male rats.


METHODS
Male rats were gavaged with either L-arginine (100 or 200 mg x kg(-1) x d(-1)), D-arginine (200 mg x kg(-1) x d(-1)) or vehicle (0.9% NaCl) for seven consecutive days. Their sexual behaviour and fertility were evaluated using receptive females.


RESULTS
L-arginine (200 mg/kg) had no significant effect on sexual competence (in terms of sexual arousal, libido, sexual vigour and sexual performance). In mating experiments, the higher dose of L-arginine effectively and reversibly inhibited fertility, whilst the lower dose and the inactive stereoisomer D-arginine had no significant effect. The antifertility effect caused by L-arginine was due to a profound elevation in the preimplantation loss mediated possibly by impairment in epididymal sperm maturation, hyperactivated sperm motility and sperm capacitation.


CONCLUSIONS
Elevated NO production may be detrimental to male fertility.
Ratnasooriya
W D
WD
Department of Zoology, University of Colombo, Sri Lanka. dappvr@sltnet.lk
Dharmasiri
M G
MG
D000818:Animals; D001120:Arginine / Q000494:pharmacology*; D004822:Epididymis / Q000187:drug effects / Q000473:pathology; D005260:Female; D005298:Fertility / Q000187:drug effects*; D005837:Genitalia, Male / Q000187:drug effects; D008297:Male; D019001:Nitric Oxide Synthase / Q000378:metabolism; D051381:Rats; D013076:Sperm Count; D013081:Sperm Motility / Q000187:drug effects
D001120:Arginine; D019001:Nitric Oxide Synthase