The role of nitric oxide (NO) in control of LHRH release that mediates gonadotropin release and sexual behavior

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#1

The role of nitric oxide (NO) in control of LHRH release that mediates gonadotropin release and sexual behavior

cat.inist.fr/?aModele=afficheN&cpsidt=14763056

Nitric oxide (NO) plays a crucial role in reproduction at every level in the organism.

In the brain, it activates the release of luteinizing hormone-releasing hormone (LHRH). The axons of the LHRH neurons project to the mating centers in the brain stem and by efferent pathways, evoke the lordosis reflex in female rats.

In males, there is activation of NOergic terminals that release NO in the corpora cavernosa penis to induce erection by generation of cyclic guanosine monophosphate (cGMP).

NO also activates the release of LHRH which reaches the pituitary and activates the release of gonadotropins by activating neural NO synthase (NOS) in the pituitary gland.

Follicle stimulating hormone (FSH)RH selectively releases FSH also by activating NOS. Leptin releases LHRH by activating NOS to release FSH and LH with the same potency as LHRH.

These actions are mediated by specific receptors on the gonadotropes for LHRH, FSHRH and leptin. The responsiveness of the pituitary is controlled by gonadal steroids.

In the gonad, NO plays an important role inducing ovulation and in causing luteolysis; whereas in the reproductive tract, it relaxes uterine muscle via cGMP and constricts it by prostaglandins.

#2

This is very important news, and to me definitely explains how our HPTA could go haywire from using the drug. Losing GnRH ruins the entire axis and translates into hypogonadal hormone levels.

Excellent find.

#3

Reduction in libido and fertility of male rats by administration of the nitric oxide (NO) synthase inhibitor N-nitro-L-arginine methyl ester

www3.interscience.wiley.com/jour … 1&SRETRY=0

The role of nitric oxide (NO) in libido and fertility of male rats was investigated by administration of the NO synthase inhibitor N-nitro-L-arginine methyl ester (L-NAME) (25 or 50 mg/kg/day). L-NAME caused marked reduction of precoital sexual behaviour, and a failure of most rats to mount or ejaculate during the test interval.

In most matings that were successful, recovered spermatozoa were present in normal numbers. In mating experiments, L-NAME profoundly reduced the fertility of male rats. In those animals that did succeed in mating, the quantal pregnancy and the number of implants were reduced.

After cessation of treatment with L-NAME, the fertility parameters returned close to normal. The inactive stereoisomer, D-NAME, caused none of the above effects when administered to rats.

The results suggest that NO is essential for the expression of normal libido and fertility in male rats. It is likely that NO is required both in the male reproductive tract and in the brain.

#4

Very interesting. Does this mean that we should all be hitting the l-arginine, in an attempt to boost our NO?