Sorbitol Dehydrogenase in the Lens

[pachyworthia]

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Hey folks, just came across contradictory information in FA vs. UWorld concerning the glucose -> sorbitol -> fructose pathway:

UWorld Q#934 says the lens of the eye DOES have sorbitol dehydrogenase whereas FA2012 p. 109 says "Schwann cells, lens, retina, and kidneys have ONLY aldose reductase."

If UWorld is right then this calls into question whether there is sorbitol dehydrogenase in the Schwann cells, retina, and kidneys too. The logic of FA (even if false) however is still very useful in figuring out which tissues are injured in diabetics by osmotic damage...

EDIT: Oops, didn't read the "Educational Objectives" at the bottom before posting this...it seems like UWorld is on top of their stuff. Thanks!

 

[MrBeauregard]

When I got that question in UWorld I took it as if the lens actually has sorbitol dehydrogenase, just not enough active to convert the sorbitol that accumulates into fructose.

 

[Morsetlis]

Well you already know the answer, so you just gotta postulate the correct mechanism, for the question, lol.

 

[wacritchlow]

I got this question too, and am still confused. FA doesn't just say "the lens has some sorbitol dehydrogenase that is overwhelmed in hyperglycemia," it says the lens has no sorbitol dehydrogenase.

UWorld says in normal individuals, the lens has sorbitol dehydrogenase.

So I guess FA is wrong?