In 1998, the Nobel Prize in Medicine or Physiology was awarded to three American scientists for their discovery of nitric oxide, or NO, as a signaling molecule in the body. This was no small accomplishment since NO is exceedingly complex to research. The reason for that is NO is a gas that suddenly appears in the blood and elsewhere in the body, only to disappear instantly. For years previous to the discovery of NO by these scientists, a substance produced in the blood vessels was known to provide dilation or a widening effect in the vessels. The problem was that no one could isolate it or even figure out where it originated. This mysterious substance was called the "Endothelial Relaxation Factor" because that's what it did. It causes the relaxation of the smooth muscles Within the endothelium or inner lining of the arteries. Within a short time following the recognition that the Endothelial Relaxation Factor was NO, a plethora of studies began to appear in science journals that documented the many and far-ranging effects of NO. But even before the Nobel Prize award, the power of NO was recognized as it was awarded the "Molecule of the Year" in 1992 by Science magazine.
Since then, numerous other studies have found many different functions of NO. For example, NO is involved in releasing hormones that include testosterone, growth hormone, and insulin, considered the body's three most potent anabolic hormones. In relation to testosterone, testosterone boosts NO by helping repair damaged blood vessel linings. NO is produced in the endothelial lining by activating a NO-synthesizing enzyme called eNOS, or "endothelial nitric oxide synthase." When this enzyme encounters the amino acid arginine in the blood, the arginine is immediately converted into NO. Based on this, arginine is the primary nutrient precursor for NO synthesis, although other nutrients such as folate also play a role. So, it would seem that an easy way to boost NO is to increase your arginine intake. But it's not that simple. While arginine provided intravenously always raises NO levels (as it does for growth hormone), oral arginine must get past a formidable barrier in the form of another enzyme called arginase, which degrades it in the gut before it has a chance to get into the blood and be converted into NO. Indeed, 40% of an oral dose of arginine is degraded by arginase in the gut. This doesn't mean that arginine is worthless as a NO booster, but rather that it's not the best way to boost NO unless you get it intravenously.
One example of how NO can be used for popular purposes is in the treatment of male erectile dysfunction (MED). Erection in the penis is dependent on blood flow, specifically trapping blood in the spongy tissues of the . . .
Join today and get access to this article and all past and present Newsletters, since September 2014. Each month you’ll get a new issue sent to your inbox. Subscribe today for only $10/month!