Inosine

drugbox
IUPAC_name = Inosine

---

CAS_number = 58-63-9
ATC_prefix = D06
ATC_suffix = BB05
ATC_supplemental = ATC|G01|AX02
PubChem = 6021
DrugBank = EXPT02378
C=10|H=12|N=4|O=5
molecular_weight = 268.229 g/mol
bioavailability =
protein_bound =
metabolism = Hepatic
elimination_half-life =
pregnancy_category =
legal_status = OTC
routes_of_administration =

Inosine is a nucleoside that is formed when hypoxanthine is attached to a ribose ring (also known as a ribofuranose) via a β-N₉-glycosidic bond.

Inosine is commonly found in tRNAs and is essential for proper translation of the genetic code in wobble base pairs.

Knowledge of inosine metabolism has led to advances in immunotherapy in recent decades. Inosine monophosphate is oxidised by the enzyme inosine monophosphate dehydrogenase yielding xanthosine monophosphate, a key precursor in purine metabolism. Mycophenolate mofetil is an anti-metabolite, anti-proliferative drug, used in the treatment of a variety of autoimmune diseases including Wegener's granulomatosis. The uptake of purine by actively dividing B cells can exceed 8 times that of normal body cells and therefore this set of white cells (which cannot operate purine salvage pathways) is selectively targeted by the purine deficiency resulting from IMD inhibition.

Reactions

Adenine is converted to adenosine or IMP, either of which in turn is converted into inosine (I), which pairs with Adenine (A), cytosine (C) and uracil (U).

Purine nucleoside phosphorylase intraconverts inosine and hypoxanthine.

Inosine is also an intermediate in a chain of purine nucleotides reactions required for muscle movements.

Clinical significance

It was tried in the seventies in eastern countries for improving athletic performance. Nevertheless the clinical trials for this purpose showed no improvement. [cite journal |author=McNaughton L, Dalton B, Tarr J |title=Inosine supplementation has no effect on aerobic or anaerobic cycling performance |journal=International journal of sport nutrition |volume=9 |issue=4 |pages=333–44 |year=1999 |pmid=10660865 |doi=]

Nowadays, it has been shown that inosine has neuroprotective properties. It has been proposed for spinal cord injury; [cite journal |author=Liu F, You SW, Yao LP, "et al" |title=Secondary degeneration reduced by inosine after spinal cord injury in rats |journal=Spinal Cord |volume=44 |issue=7 |pages=421–6 |year=2006 |pmid=16317421 |doi=10.1038/sj.sc.3101878] , because it improves axonal rewiring, and for administration after stroke, because observation has shown that axonal re-wiring is encouraged. [cite journal |author=Chen P, Goldberg DE, Kolb B, Lanser M, Benowitz LI |title=Inosine induces axonal rewiring and improves behavioral outcome after stroke |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=99 |issue=13 |pages=9031–6 |year=2002 |pmid=12084941 |doi=10.1073/pnas.132076299 |url=http://www.pnas.org/cgi/content/full/99/13/9031] .

It is currently in phase II trials for multiple sclerosis (MS) [ [http://www.clinicaltrials.gov/ct/show/NCT00067327 Treatment of Multiple Sclerosis Using Over the Counter Inosine - Full Text View - ClinicalTrials.gov ] ] . It produces uric acid after ingestion, which is a natural antioxidant and a peroxynitrite scavenger, which can suggest possible benefit in multiple sclerosis [ [http://www.geocities.com/hotsprings/3468/uric_acid-peroxynitrite2-98.html Uric Acid: Natural Scavenger Of Peroxynitrite ] ] (peroxynitrite has been correlated with the axons degeneration [http://www.fedem.org/revista/n17/neuhausing.htm] ).

Alseres Pharmaceuticals (named Boston Life Sciences when patent was granted) patented the treatment for stroke [http://www.bostonlifesciences.com/news111.htm] and is currently investigating the drug in the MS setting [Alseres pharma drug description [http://www.alseres.com/product-pipeline/product-candidates/inosine.asp] ] .

Biotechnology

When designing primers for polymerase chain reaction, inosine is useful in that it will indiscriminately pair with adenine, thymine, or cytosine. This allows one to design a primer that spans a single nucleotide polymorphism, without worry that the polymorphism will disrupt the primer's annealing efficiency.

Fitness

Despite a lack of clinical evidence that it improves muscle development, inosine remains an ingredient in some fitness supplements.

ee also

*Inosine monophosphate dehydrogenase

References

External links

* [http://www.pdrhealth.com/drug_info/nmdrugprofiles/nutsupdrugs/ino_0144.shtml PDR health study]