|Image 1: This is what NO boosters|
promise, yet mostly don't deliver.
If arginine does not work, this does not mean that NO does not work either!
Those of you who have listened to my dissertation on amino acids, in the Amino Acids For Super Humans series on Carl Lanore's Super Human Radio, will yet probably remember that I mentioned a couple of test-tube studies, in which the incubation of intact myotubes with high amounts of l-arginine induced a profound growth response. Moreover, slightly more recent evidence from the Center of Exercise Science at the University of Florida points to the involvement of nitric oxide in the release of PGC-alpha, about the far-reaching metabolic effects (increase in mitochondrial density, effectivity and via irisin "browning of the fat cells", cf. PGC-alpha, irisin) you have read several times, already, here at the SuppVersity - and, as of late, probably even heard of in mainstream media.
|Image 2: MP Assault is currently #2 in the Top 50 Best Selling Products over at BB.com, it is yet only 1/3 purported NO-boosters in the Top 10|
Isosorbide dinitrate, a real NO booster
In their study, Jeff R.S. Leiter and his colleagues did not even bother with l-arginine, but chose a pharmacological NO donor, which is usually prescribed to patients suffering from angina pectoris: Isorsorbide dinitrate, a long acting form of nitrates that is sold under the brand names Isordil, Cedocard, Sorbitrate, etc. To evaluate whether the administration of this medication could help combating the age-induced decline in satellite cell activation and subsequent loss of skeletal muscle mass, the scientists treated 18-months old female C57BL/6 mice (in human terms those mice were grannies) with either 66mg/kg isosorbide dinitrate (human equivalent: 5mg/kg) or placebo for 6 weeks. In addition to the "supplementation", half of the mice had free access to one of those tiny wheels, of which mice - contrary to the lazy human beings for whom they are used as a model - usually avail themselves voluntarily. Altogether, this leaves us with 4 groups:
- Control group: no wheel running, no NO donor
- Exercise group: access to wheel, no NO donor
- Treatment group: no access to wheel, 66mg/kg isosorbide dinitrate
- T + EX: access to wheel, 66mg/kg isosorbide dinitrate
|Figure 1: Muscle weight of skeletal muscle of exercised and/or isosorbide dinitrate treated 18-months old mice after 6-weeks (data adapted from Leiter. 2012)|
|Figure 2: DNA synthesis and vascular density in skeletal muscle of exercised and/or isosorbide dinitrate treated 18-months old mice after 6-weeks (data adapted from Leiter. 2012)|
Would the combination of an effective NO donor with leucine/HMB work even better?
What is yet interesting, though is that in those "old ladies" the exercise induced skeletal muscle protein synthesis obviously could not keep pace with the increase in DNA expression.
|Figure 3: Mean fiber diameter and protein synthesis in skeletal muscle of exercised and/or isosorbide dinitrate treated 18-months old mice after 6-weeks (data adapted from Leiter. 2012)|
|Image 3: For patients with angina pectoris, |
these small sublingual tablets are life-saving,
for the average physical culturist, they
pose a non-negligible health risk.