PHARMACODYNAMICS Studies have demonstrated that a deficiency in queuine in in-vitro human cells and in animals results in a decreased level of the cofactor tetrahydrobiopterin (BH4) [A173830, A173833]. Since BH4 is a necessary cofactor for the transformation of phenylalanine to tyrosine, of tryptophan to serotonin, of tyrosine to dopamine (dopamine, which itself is further converted into epinephrine and norepinephrine), of arginine to nitric oxide, and for the oxidation of alkyl glycerol lipids [A173830, A173833], it is proposed that queuine plays an important pharmacodynamic role in the generation and maintenance of these essential biochemical compounds [A173830, A173833, A173851].

ROE Data regarding the route of elimination of queuine is not readily available or accessible.

INDICATION Current and on-going research suggests queuine is a natural biochemical compound that can be found endogenously in the human body and plays an essential role in the generation of other critical bodily chemicals including tyrosine, serotonin, dopamine, epinephrine, norepinephrine, nitric oxide, lipids, and others [A173830, A173833, A173851]. Such research subsequently proposes that if queuine could be utilized as a pharmaceutic, that it may be considered a so-called 'putative longevity vitamin' indicated for age-delaying and/or prolonged survival functionality (perhaps via maintaining the ongoing generation of the aforementioned bodily chemicals) for the human body [A173830, A173833, A173851].

TOXICITY Queuine is a natural biochemical that can be found endogenously in the human body [A173830, A173833, A173851]. Although certain studies on mouse models have shown that a deficiency in the agent can have fatal consequences [A173830, A173833, A173851], data regarding toxicity or overdosage of queuine is not readily available or accessible.

METABOLISM Data regarding the metabolism of queuine is not readily available or accessible.

ABSORPTION Humans recover queuine from either ingested food or the gut flora [A173830, A173833, A173851]. The proportion of queuine salvaged and absorbed from the normal turnover process of human microbiota has not yet been determined, but it may be significant given the number of microorganisms in the human gastrointestinal tract [A173830]. Furthermore, it is believed that there may exist a dedicated transporter for queuine, considering various purines, purine-derivatives and base analogs are incapable of affecting queuine transport in competitive uptake experiments [A173830, A173833].

HALF-LIFE Data regarding the half-life of queuine is not readily available or accessible.

MOA Certain studies have shown that queuine-deficient mice became tyrosine deficient and expired within eighteen days of being withdrawn from a queuine containing diet [A173833]. Considering tyrosine is generally a nonessential amino acid, it is presumed that the expiration of the mice was due to a resultant deficiency in the cofactor tetrahydrobiopterin (BH4) (which does contribute to the generation of tyrosine), the endogenous generation of which queuine is believed to contribute to [A173830, A173833]. As a result, one of the potential mechanisms of action by which queuine may act as a vitamin for age-delaying and/or prolonged survival functionality speaks to the plausible essentiality of BH4 for partaking in activities like the hydroxylation of tryptophan to produce serotonin for numerous neurological functions like controlling executive function and playing a part in the pathophysiology of autism, attention-deficit/hyperactivity, bipolar, and schizophrenia disorders [A173830, A173833]. Elsewhere, another study has also demonstrated that queuine and the use of a synthetic analog have been effective in eliciting full remission in a mouse model of multiple sclerosis, particularly via the importance of tRNA guanine transglycosylase (TGT) present in the animal model to utilize the queuine analog substrate [A173833, A173851]. Essentially, animals deficient in TGT are incapable of using queuine or any synthetic analog of the biochemical to modify tRNA to produce queuosine for further related downstream pharmacodynamics and fail to respond to such therapy [A173833, A173851]. Although the specific mechanism of action beyond these actions has not yet been formally elucidated, these actions suggest that some manner of modulation of protein translation may be the principal means via which this therapeutic effect is elicited [A173833, A173851]. In human cells, queuine tRNA-ribosyltransferase (QTRT-1) interacts with queuine tRNA-ribosyltransferase subunit QTRTD1 to form an active queuine tRNA-ribosyltransferase [A173830, A173833, A173851, L5083]. This enzyme exchanges queuine for the guanine at the wobble position of tRNAs with GU(N) anticodons (tRNA-Asp, -Asn, -His and -Tyr), thereby forming the hypermodified nucleoside queuosine [A173830, A173833, A173851, L5083].

MOA Certain studies have shown that queuine-deficient mice became tyrosine deficient and expired within eighteen days of being withdrawn from a queuine containing diet [A173833]. Considering tyrosine is generally a nonessential amino acid, it is presumed that the expiration of the mice was due to a resultant deficiency in the cofactor tetrahydrobiopterin (BH4) (which does contribute to the generation of tyrosine), the endogenous generation of which queuine is believed to contribute to [A173830, A173833]. As a result, one of the potential mechanisms of action by which queuine may act as a vitamin for age-delaying and/or prolonged survival functionality speaks to the plausible essentiality of BH4 for partaking in activities like the hydroxylation of tryptophan to produce serotonin for numerous neurological functions like controlling executive function and playing a part in the pathophysiology of autism, attention-deficit/hyperactivity, bipolar, and schizophrenia disorders [A173830, A173833].; ; Elsewhere, another study has also demonstrated that queuine and the use of a synthetic analog have been effective in eliciting full remission in a mouse model of multiple sclerosis, particularly via the importance of tRNA guanine transglycosylase (TGT) present in the animal model to utilize the queuine analog substrate [A173833, A173851]. Essentially, animals deficient in TGT are incapable of using queuine or any synthetic analog of the biochemical to modify tRNA to produce queuosine for further related downstream pharmacodynamics and fail to respond to such therapy [A173833, A173851]. Although the specific mechanism of action beyond these actions has not yet been formally elucidated, these actions suggest that some manner of modulation of protein translation may be the principal means via which this therapeutic effect is elicited [A173833, A173851].; ; In human cells, queuine tRNA-ribosyltransferase (QTRT-1) interacts with queuine tRNA-ribosyltransferase subunit QTRTD1 to form an active queuine tRNA-ribosyltransferase [A173830, A173833, A173851, L5083]. This enzyme exchanges queuine for the guanine at the wobble position of tRNAs with GU(N) anticodons (tRNA-Asp, -Asn, -His and -Tyr), thereby forming the hypermodified nucleoside queuosine [A173830, A173833, A173851, L5083].