Do you wonder why?

[chbare]

Do you ever wonder why things are called what they are? Simple, every day concepts we often discuss have deeper meaning behind their name. So, why not dedicate a thread to these concepts?

So, let's start off with a very common one. Why do we call glucose, dextrose? Is there in fact something special about dextrose? Is all glucose the same? What is a primary difference? Trust me, understanding this concept will go a long way in helping you understand how it applies to other medications.

Take care,

chbare.

[funkytomtom]

I can't offer any wisdom, but I'm definitely listening.

[Fignewt345]

So, let's start off with a very common one. Why do we call glucose, dextrose? Is there in fact something special about dextrose? Is all glucose the same? What is a primary difference? Trust me, understanding this concept will go a long way in helping you understand how it applies to other medications.

Why do we call glucose, dextrose?

Because dextrose is one of the two forms of glucose.

Is there in fact something special about dextrose?

Yes, dextrose (dextrose monohydrate, or dextroglucose) is by far the more common and the only form of glucose our cells can use for glycolysis.

Is all glucose the same? What is the primary difference?

No, both forms of glucose (the other being the rare levoglucose which is normally not naturally occuring) may have the same molecular formula and molecular sequence, however their structures are different in that they are basically mirror opposites of one another. They have opposite molecular configurations.(enantiomers)

[chbare]

Good, so glucose has multiple forms; however, nature tends to favor the D form of glucose. This form is what we commonly call dextrose. You are correct in that dextrose is the D enantiomer of glucose. An enantiomer is a type of stereoisomer that has a "mirror image" characteristic. Additionally, there are profound optical differences between D & L. Passing polarized light over a D enantiomer will cause the light to move clockwise in what we call dextrorotary. Likewise, a L will cause the light to move in a counterclock wise direction called levorortory.

Is there an easy way to tell D from L? Does the difference between D and L potentially effect humans?

Take care,

chbare.

[Fignewt345]

Is there an easy way to tell D from L?

I don't know of any simple way of distinguishing between the two in everyday uses. Glucose synthesis can be achieved by photosynthesis in plants, and anabolic reactions (gluconeogenisis) in plants, animals (e.g. liver) etc. The glucose synthesized naturally will be in the form of d-glucose. Therefore, am I safe to assume readily available means of testing is not normally needed?

Does the difference between D and L potentially effect humans?

Our metabolism is stereoselective, and l-glucose is not broken down in glycolysis. l-glucose does have laxative effects and some studies have shown it to be a fairly benign and safe pre-colonoscopy laxative. A quick search revealed some studies on the effects of l-glucose and increased memory in rats (along with other monosaccharides), but I did not come across any widely published reports on the effects of l-glucose in humans. However, an anomer derivative of l-glucose can have the opposite effect on the langerhans islets beta cells in the pancreas by stimulating insulin release. So giving this form of l-glucose sugar may actually have the opposite effect compared to traditional d-glucose treatments. I am unsure of the prevalence of this form of l-glucose, so I can't say if this is a real danger.

However, I'm always willing to be surprised if you got any more information for us.