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RE: [RC] Where is selenium high/low? - heidiI have no scientific proof of this hypothesis, but I always believed (given the known role of selenium as a cofactor in >enzyme functions in cell membranes) that the selenium-deficient cells of the lining of the GI tract were incapable of taking >up the very selenium that they needed, but once they had some on board, they worked just fine at getting it out of the gut. That sounds like a reasonable hypothesis to me. We know there are other failures in GI uptake when the system is starved of that substrate, thus many of the developments in parenteral nutrition under extreme conditions. ========================= Could you give an example of that please? Selenate is absorbed across cell gaps along a concentration gradient so wouldn't require any active cellular uptake. Selenite needs to be complexed to thiols to be absorbed, while organic forms are picked up by the cell receptors for the specific amino acid. These CA/Oregon horses that require massive doses are fascinating. I've had hays test for selenium below the detection limit but horses responded just fine to 2 to 3 mg/day (NOT endurance). I searched but couldn't find any recommendations from Oregon State for 9 to 10 ppm in equine diets. Is there an online link? Any idea if there may be high levels of one or more minerals that could be blocking absorption? Sorry, no links--this goes back to the pre-internet days, when we got stuff in the mail through the university's extension service, and either called them or wrote to them when we had questions. :-) No, there didn't seem to be anything else significantly blocking selenium, and given that there was no problem once the levels were up, that doesn't seem like a logical explanation. Susan's similar experiences in a different part of the country would also make me leery of the idea that we had some other mineral imbalance causing the problem. You may well have answered your own question, given that much Se is in the form of selenites--I'll take your word for it that they must be bonded with thiols, but that process may not be able to happen properly if the cells are highly deficient. As for having to do with membrane function, there was some great research done on white blood cells in cattle (beef calves, if memory serves) that showed WBCs with adequate selenium merrily phagocytizing bacteria, but deficient WBCs working and working at it and never able to get their membranes to enclose them. Lots of good research on selenium and immune function in the cattle industry, particularly pertaining to scours and pneumonia... As I said, this is just my hypothesis... Heidi =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Ridecamp is a service of Endurance Net, http://www.endurance.net. Information, Policy, Disclaimer: http://www.endurance.net/Ridecamp Subscribe/Unsubscribe http://www.endurance.net/ridecamp/logon.asp Ride Long and Ride Safe!! =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
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