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fireside3
at Sun Dec 3 04:05:25 2006 [ Report Abuse ] [ Email Message ] [ Show All Posts by fireside3 ]
Neutralization by Horned Lizard of formic acid through reaction with blood borne Calcium.
For some time those of us who have studied HL for a few years have heard numerous stories of a mystical substance contained in the blood of the HL, which is supposed to neutralize the formic acid from Pogo harvester ants. The story goes; that if the lizard does not receive harvester ants, or formic acid, this substance will build up and poison the lizard ( killing it ). For many years I have discounted this unsubstantiated mystery reference as hyperbole. Though I still believe it more or less to be hyperbole, I have recently reconsidered the basic tenets. Primarily the assumed "immunity" to harvester ant venom and any neutralization action.
An acid can be neutralized by a base of course. Calcium carbonate is a base salt and as we know is carried in the blood in a certain balance. Insufficinet calcium causes MBD as we know. When formic acid is neutralized by the base calcium carbonate, where water is present ( such as in the blood ), the product would be salt, CO2, and EXTRA water from the carbonic acid component of formic acid. This would also better explain the questions of excess salt excretions by the HL.
Calcium carbonate is much more soluble also when CO2 is present, making this reaction with formic acid very benificial to the HL's use of it in proper bone growth. The CO2 is then carried by the blood to the lungs and expelled. I just find that fascinating. Anyone else?
Lester-I have a few biology related questions:
1. Is there any evidence to support a belief that the HL maintains a higher normal Ca. concentration in it's blood than any other lizard? 2. Reaction path-Is it a safe assumption that the HL "neutralizes/metabolizes" formic acid in it's blood by action with blood borne Ca.?
3. Is there any basis to support a belief that HL's have an advantage in proper growth and prevention of MBD when offered harvester ants ( per my post on P,Ca. solubility/digestability with formic acid)? 4. What effect does the excess ( beyond what is produced by normal respiration ) CO2 ( from formic acid metabolization ) have on oxygenation of the blood in the HL? Could this also explain their defensive/camouflage traits, as having something to do with a reduced availability of O2 in the blood for fleeing quickly, and great distances, compared to other lizards? ( I think it may be insignificant, but I'm reaching anyway.) Has anyone even researched these avenues before?
Outside of improper captive care ( offering excessive Ca. supplements ), I don't believe there is any evidence that Calcium would build up ( hypercalcemia ) and cause a problem without formic acid. If the HL is able to keep up with the Ca. intake, it will simply pass excess Ca. the same as any other reptile. But, I am "discovering" new avenues and questions to research which is pointing toward Pogos having more significance than even I knew before. I'd appreciate input from someone with a strong biology background. ----- "A man that should call everything by it's right name, would hardly pass the streets without being knocked down as a common enemy." The Complete Works of George Savile, First Marquess of Halifax 1912,246
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