Hi,
I am a bit confused on the actual levels that are used in EtG testing: Most european studies I have read use .1mg, but I have read a bunch of studies referring to 100NG... they don't seem to be the same level. If the lab that is testing you is using 100ng then the detection would be much longer than what the studies that use .1mg say? Is that right? Any ideas on how much time that might add?

Also grapefruit juice in one presentation is said to reduce ETG production. The best I can find is that grapefruit juice effects or inhibits certain enzyme productions (cyp450? etc)... so does that in effect reduce the ETG metabolite? I know it will effect the metabolic rate of a variety pharma drugs.

Any thoughts out there

The metric used is the same simply expressed differently. In the US it is ng/ml. Milligrams are parts per million per liter (EU), while the US uses parts per billion per milliliter.

95+% of all EtG studies derive from Germany and Sweden. Some are Americanized for the journals but otherwise a simple rule is to convert .1 to 100, 5 to 500 etc. You are right to watch that carefully because the method might vary from study to study. At any rate they are using the same standard.

Grapefruit juice does inhibit some P450 enzymes but it is a selective inhibition. P450 family is large and CYP2E1 is the subgroup most active in ethanol metabolism in the oxidative stage (Phase I).

I believe that you are looking in the wrong direction. As opposed to inhibiting the metabolic process it is advantageous to accelerate the process. EtG is a direct metabolite of EtOH and so long as EtOH is present EtG will be produced in Phase II. EtG synthesis ceases at BAC=0. Don't want to delay that process. The more efficiently the liver is metabolzing the EtOH the faster EtG synthesis ends, peaks and then begins elimination, also dependent on metabolic rate.

Thanks... so most of the studies used the 100ng level as their cutoff.. good to know
I had just seen in a presentation that grapefruit actually reduced ETG while some other foods increased it. So is it possible that Grapefruit Juice actually increases your metabolic process? Perhaps that what the presenter was getting at (G Skipper presentation)

I was looking at study from Helander, Bottcher,Fehr... (2008) table 1 list cutoffs at mg/L... so .1 in these instances are equal to 100ng? Just wanted to make sure

Thanks for your help

Thanks...so most of the studies used the 100ng level as their cutoff..good to know
I had just seen in a presentation that grapefruit actually reduced ETG while some other foods increased it. So is it possible that Grapefruit Juice actually increases your metabolic process? Perhaps that what the presenter was getting at (G Skipper presentation)

I was looking at study from Helander, Bottcher,Fehr...(2008) table 1 list cutoffs at mg/L...so .1 in these instances are equal to 100ng?? just wanted to make sure

Thanks for your help

Where did you read that grapefruit juice reduced EtG? I'm familiar with Greg Skipper but not the association with the juice. Yes the Helander study references a .1g/L, 100 ng/mL cutoff.

Very interesting study. Claims a 130 hour detection window, while it was actually the result of drinking or exposure. (Fig. 4)

Everything I've encountered on grapefruit juice indicates that it inhibits P450 selected enzymes but not CYP2E1. In order for it to increase metabolism it would need to induce, not inhibit, enzymes. I haven't researched grapefruit juice at all so it may be something that I have missed.

This link below should work... it is the 19th slide in.. I just have not found another reference
He says greens increase it? I just don't have the bio background to understand the science


Testing for Alcohol Use Understanding EtG, EtS,. *Genetics-↑↓ *Chronic use-↑until-liver failure↓ *Foods *grapefruit juice↓,.

Tadcptn.org/pAlcohol%20Markers.%20Webinar.Testing%20for%20Alco hol... · PDF file

Let me know if you a need a better url

http://tadcptn.org/pAlcohol%20Markers.%20Webinar.Testing%20for%20Alco hol%20Use.v9.print.version.pdf

Maybe this is better... so .1mg/L is =100ng right or is it .1mg/l=1000ng? Sorry, just not sure of your answer. Hope the above address is better

thanks so much

http://tadcptn.org/pAlcohol%20Markers.%20Webinar.Testing%20for%20Alco hol%20Use.v9.print.version.pdf

Maybe this is better...so .1mg/L is =100ng right or is it .1mg/l=1000ng?? sorry, just not sure of your answer. hope the above address is better

thanks so much

They are using either a 100 or 500 ng cutoff.

I found his presentation. I'll go back and look for an association for grapefruit juice. I had read his presentation previously but never looked into it. Thus far it doesn't follow but maybe I should be looking more directly at Phase II enzymes.

Dr Bill.. hope you found the presentation.. it clarifies that detection level just like you said-thanks
The slide refers to cyp450 enzyme... just don't know how that fits??

Any further thoughts?

http://tadcptn.org/pAlcohol%20Markers.%20Webinar.Testing%20for%20Alco hol%20Use.v9.print.version.pdf

Dr Bill..hope you found the presentation..it clarifies that detection level just like you said-thanks
the slide refers to cyp450 enzyme...just don't know how that fits????

Any further thoughts??

I don't have a problem with grapefruit juice (GPJ) inhibiting specific P450s. But there are 18 families of cytochrome P450 genes and 43 subfamilies. I find nothing to indicate an effect on the primary family that is active in alcohol metabolism and particularly in glucuronidation. I am going to look at a system more directly involved in glucuronidation called UGTs. It may be tomorrow when I can appropriate a starry eyed research assistant.

Usually Dr. Skipper doesn't provide misinformation (he may shade it a bit), so it's worth looking further. Thanks for bringing it to my attention.

Thanks for your time... I haven't been drinking, but I start having grapefruit juice as I anticipate I am going to test. So far so good... but it really doesn't say anything because I haven't had any ethanol. But it would be valuable to know what exactly the grapefruit juice has the potential to disrupt. I know it does effect certain drugs, etc... maybe it is something the test marketers don't want to talk about.

If you could let me know what you find out that would be great. Thanks for all your help.

Thanks for your time...I haven't been drinking, but i start having grapefruit juice as I anticipate I am going to test. So far so good...but it really doesn't say anything because I haven't had any ethanol. But it would be valuable to know what exactly the grapefruit juice has the potential to disrupt. I know it does effect certain drugs, etc...maybe it is something the test marketers don't want to talk about.

If you could let me know what you find out that would be great. Thanks for all your help.

Grapefruit juice = GFJ

I believe I pegged it out of the gate. Anything that inhibits P450 metabolism (ie GFJ) would necessarily keep the substance in system for a longer period. GFJ does not seem to influence (P450)CYP2E1 in either direction and CYP2E1 is the enzyme active in ethanol metabolism.

I was surprised at the number of drugs and enzymes that are inhibited by GFJ. My RA turned up an interesting website that lists the various P450s by family and categorizes the specific drugs each metabolizes. That should be of interest to you: See P450s in Drug Metabolism (http://biocomp.health.unm.edu/p450/metabP450diseasep3v06.pdf)

EtG is an alternate metabolic route, something like an overflow system, for EtOH metabolism. It handles about .015-.2 % of the EtOH dose. Therefore when EtOH metabolism is slowed either by ADH* or P4502E1 the greater the overflow into this non-oxidative pathway. That would lead to more, not less, EtG. This issue is addressed, at least hypothetically, in Hoiseth, 2008 (http://alcalc.oxfordjournals.org/content/43/2/187.full?sid=5cf8d521-9b3e-49a3-a597-a10c9f4ed2b1) Discussion.

When looking to reduce EtG synthesis (Phase II) the most expedient route is to increase (induce) those enzymes active in Phase I metabolism at the level of ADH and P450 2E1.

Why Dr. Skipper advanced this claim (in presentation noted) is unknown to me but the information is inconsistent with the existing body of reaearch. As you will note, Skipper lists his address and phone number thereon. He also has two (2) websites: Greg Skipper, MD (http://gregskippermd.weebly.com/) and Ethylglucuronide/Ethyl Sulfate (http://http://etg.weebly.com/), both offering professional information

While no claim was made of involvement of UGTs**, since related, I looked into induction and inhibition and found nothing that would support the idea of EtG reduction via GFJ.

My conclusion is that GFJ has no effect on EtG synthesis, and that any possible effect would be to create more EtG and not less. I realize that this contradicts Dr. Skipper's publishment and have notified him of same, requesting clarification, via the website noted above. You may wish to do address your question there as well.

Should you have further questions, just ask.

*Alcohol Dehydrogenase
** UDP-glucuronosyl-transferase

Wow. Thanks for your response... I will send a note to him as well. Unfortunately I am a bit daunted by the biology. So I assume you are saying that gfj does not affect the enzyme that could alter EtG production. Perhaps it may actually slow things a bit to cause EtG to be actually larger.

Perhaps skipper has some other insight?

Thanks again... please let me know if he responds... I will let you know as well

Wow. Thanks for your response ...I will send a note to him as well. Unfortunately I am a bit daunted by the biology. So I assume you are saying that gfj does not affect the enzyme that could alter etg production. Perhaps it may actually slow things a bit to cause etg to be actually larger.

Perhaps skipper has some other insight?

Thanks again...please let me know if he responds...I will let you know as well

Shanty,

I am personally gratified... you received the exact message that I meant to transmit.

Grapefruit juice "does not affect the enzyme that could alter etg production. Perhaps it may actually slow things a bit to cause etg to be actually larger."

While the issue of GFJ may be minor, the science underlining the observation is extremely important.

Does Dr Skipper have some "other insight"? Hopefully!

In the meantime let me solidify my position and state that you can drink all of the GFJ you can hold and it will not alter the rate of production of EtG.

Hi DrBill... So,
• Substrates / Inhibitors for CYP2E1
• Cimetidine
• Disulfiram
• Propofo

These drugs inhibit the enzyme that effect the metabolism of ethanol... one is Antabuse and the other is I believe the drug they blamed on Michael Jackson's death... but Cimetidine is Tagamet, a nexium like drug. So does Tagamet reduce ETG production or actual end up increasing it. If ethanol is not metabolized then EtG would not be produced right? So people on Tagamet would may be shooting off false negatives if they are drinking. I just found that site really interesting

Thanks

Hi DrBill...So,


These drugs inhibit the enzyme that effect the metabolism of ethanol...one is Antabuse and the other is I believe the drug they blamed on Michael Jackson's death...but Cimetidine is Tagamet, a nexium like drug. So does Tagamet reduce ETG production or actual end up increasing it.? If ethanol is not metabolized then etg would not be produced right? So people on Tagamet would may be shooting off false negatives if they are drinking. I just found that site really interesting

Thanks

The site is easy to follow. Better than the one I was using previously.

There are numerous drugs that slow (inhibit) EtOH metabolism. Aspirin is the most prominent. You will have no difficulty finding numerous means and methods to slow alcohol metabolism.

Let me phrase it a little differently. If you slow EtOH metabolism then you simply get drunk faster and stay drunk longer by delaying the processes of elimination. Now my theory is that if you slow metabolism at the level of ADH or by inhibiting P450 (both Phase I) functions then Phase II (where EtG is synthesized) would work harder to pick up the slack. Thereby increasing EtG production. That is consistent with Hoiseth (cited above). Of course that is untested.

For the sake of argument let's assume that P450 inhibition doesn't result in more EtG. The fact that hepatic metabolism is slowed would mean that EtG is created at a slower pace and remains in the system longer. The rate of elimination slows and consequently it is detectable for a longer period.

Dr Bill... I got answer back from Dr Skipper.. He said that the info on the grapefruit juice and the cp450 was most likely a mistake.. so I appreciate you working through the biology . I think he should have been a little more careful with his presentations.

Thanks again

Dr Bill...I got answer back from Dr Skipper..He said that the info on the grapefruit juice and the cp450 was most likely a mistake..

Glad we got rid of the grapefruit juice idea and particularly that you took the time to check the original source of the information. So important in distinguishing myth from reality.

As a reward for your persistence here is a tip: Check fructose.

Let me know what you think.

Dr Bill... thanks for the frucrose idea
Now using what you told me... it seems like that helps with the elimination of ethanol quicker, so EtG would be created earlier, hence it might shorten up the detection window right? But... it doesn't really effect EtG levels or elimination.. right?. meaning your BAC would go to zero quicker

Did I miss something

Best regards