The above chart is from a study summary done in 2006 called
Nuclear ADP-Ribosylation Reactions in Mammalian Cells: Where Are We Today and Where Are We Going?http://mmbr.asm.org/...t/70/3/789.fullIts a good read but more recent studies may have improved on what was known then.
Assuming that the information is still good; the chart is great for seeing what is required to increase NAD+ while decreasing SIRT limiting Nam, but is not the whole picture:
Ribose sneaks into and out of the picture with hardly a mention!?
Below are my observations, research leads and questions about these pathways:
1: The salvage of NR?The only study looking at what happens to NR once ingested says NR is "...slowly cleaved by an enzyme associated with the mucosal cells to nicotinamide..." and that "...NR was not found in intestinal tissue or the perfusate fractions..."
http://jn.nutrition..../113/2/412.longhttp://www.longecity...ndpost&p=690504This study is old and a subsequent studies may have proved it wrong?
Does anybody have any more recent info?
Nicotinamide Riboside feeds into this NamPT salvage pathway between Nam and NAD+. As such it looks like NR will increase NAD+, but this increase will lead to less need for using up/decreasing Nam and hence less SIRT?
2: The salvage of Nam.If you follow the path from NAD+ to Nam NAD+ is hydrolysed by PARP, MART, SIRT, etc. which releases the Nam from NAD and produces a whole lot of Ribose containing substances, right up to 5-phosphribosyl-1-pyrophosphate. (PRPP)
Starting with NAD+ and working back to Nam its easy to see that we want to improve the NAM salvage pathway by increasing nicotinamide phosphoribosyl transferase (NamPT) and nicotinamide mononucleotide adenylyl transferases (Na/NMNAT-1, -2, and -3), respectively.
3: The salvage of NA.PRPP is also used up in the salvage of NA, so supplementing with it might decrease the amount available for the salvage of Nam?
4: ATP.ATP is used up all over the place in these pathways, so is there sufficient ATP for these processes and is it in the right places?
5:
Phosphate and other minerals etc.Phosphate in numerous forms is all over the place
6: Ribose.
What the chart doesn't show is where Ribose comes into and leaves the picture??
"ATP (3 phosphates) is converted to ADP (2 phosphates) with the release of energy for work. ADP passes into the mitochondria where ATP is remade by oxidative phosphorylation (ie a phosphate group is stuck on). ATP recycles approximately every 10 seconds in a normal person
If ATP levels drop as a result of leakage of AMP, the body then has to make brand new ATP. ATP can be made very quickly from a sugar D-ribose, but D-ribose is only slowly made from glucose via the pentose phosphate shunt... This takes anything from one to four days"
http://www.drmyhill....ondrial_FailureIt seems to be a common practice to emphasise one part of a molecule in a supplement and not mention the other, important part, for the sake of profit.
Magnesium L-Threonate comes to mind as a good example. It turns out that L-Threnate does way more than make the magnesium bioavailable:
MAGNESIUM L-THREONATE is NO more effective than SULFATE form
http://www.longecity...n-sulfate-form/L-Threonate for neurogenesis, alzheimer's, hair loss, osteoarthritis
http://www.longecity...osteoarthritis/The better Vitamin B complexes have many the B as a phosphate..?
Ribose is present in NAD and seems to leave the picture with PRPP.
Nicotinamide looks the worst choice for maximising NAD+ while minimising SIRT limiting Nicotinamide.
Nicotinic Acid Riboside seems like a better choice except for the fact that its Hygroscopic and needs to stored at -20˚C in an inert atmosphere.
http://www.trc-canad...inic Riboside�;As I have said before:
http://www.longecity...ndpost&p=690504I think it likely that NR is nothing more than a slow release Nicotinamide and Ribose combo?
Research/info on the Ribose metabolism/production would be great if anyone has any?
Research Leads:
Resveratrol
This study shows that Resveratrol increases NAMPT and SIRT1 in healthy liver cells while decreasing the same in cancerous cells leading to apoptosis!
I have not looked into whether the dosage used is attainable in vivo, but there is similar info on the forum.
http://www.plosone.o...al.pone.0091045http://www.longecity...atrol-thus-far/Circadian Control of the NAD+ Salvage Pathway by CLOCK-SIRT1
http://www.schulenbe.../05.08.09.1.pdfThis study was done on mice which are nocturnal? and is not an easy read.
It would be nice if a consensus could be reached on the best timing for the use of different NAD+ increasers.
I'm guessing we will to increase NAD+ at night as Resveratrol is a pro-oxidant during the day-time and an antioxidant at night/
http://www.ncbi.nlm....pubmed/19695122Inositol hexanicotinate
This looks interesting if it is found that a slow release of NA is desired. (if there's no 'amide' in the word its NA)
I have not yet found any source of slow release Ribose beside NR.
https://www.scribd.c...-Health-EffectsOops; I hit post in stead of preview.
More coming.
Edited by Logic, 17 October 2014 - 07:36 PM.