Nope - you Brits have no sense of humor at all. <img src="/forums/images/graemlins/lol.gif" alt="" /> But you do have a sense of humour - whatever that is. <img src="/forums/images/graemlins/wink.gif" alt="" />

Frank <img src="/forums/images/graemlins/cheers.gif" alt="" />

<img src="/forums/images/graemlins/lol.gif" alt="" />

Well, in that case... I'm not sure I would use the word 'opinions' though. Anything taken seriously must be, at the very least, a well thought out hypothesis. Of course, a hypothesis must extend from what is known already. However, even pretty convincing evidence can be overturned by something new and more powerful.

One such situation, which I teach to students, and involves lactic acid. Most think it's a waste product and makes our muscles sore after exercise. It does nothing of the sort as we now know. Interestingly, if you remove the newer data about lactic acid the old theory becomes convincing again, albeit with gaps.

This is why it's so important to view science kind of like a perpetual lava flow. Always moving steadily, with new lava covering the old, but the old is still there if you look for it. Or something like that anyway <img src="/forums/images/graemlins/cyclops.gif" alt="" /> Of course some theories, no matter how much you scrutinize them, using new tools and technology they still make complete sense to those who care to understand them. Newton, Darwin, Einstein for example <img src="/forums/images/graemlins/cheers.gif" alt="" />

I did not know that the old theory was wrong. When did they figure that out and what is the current idea? PM me response so you can keep this on topic.

No way! Post it up. I want to know too.

So, they had it wrong in A Few Good Man???

Umm... Isn't it rather difficult to have many of one?

It's easy to have one of many though.

OK, got a little time.

So most of you who went through this in school biology class were probably told that the end product of glycolysis (remember, the initial anaerobic breakdown of glucose or glycogen?) was pyruvate. Pyruvate then enters mitochondria, looses a carbon and a hydrogen, becoming the 2 carbon molecule Acetyl-CoA (with me so far?). Acetyl-CoA enters the Krebs Cycle by combining with the 4 carbon oxaloaccetate to make the 6 carbon citrate and off it goes around Krebs (I doubt it's really a circle <img src="/forums/images/graemlins/lol.gif" alt="" />). If glycolysis goes too fast, the extra pyruvate cannot enter the mitochondria fast enough and so any leftover is converted to lactate and sent out of the cell causing a rise in blood lactate, fatigue and muscle soreness 1-2 days later. Sound OK?

There are three principle problems with this idea;

1. A reduced NAD (NADH) needs to be oxidized back to NAD to be reduced again during the 2nd phase of glycolysis. If this doesn't happen, glycolysis will slow or even stop...that's a problem! The NADH can be oxidized by lactate dehydrogenase by converting pyruvate to lactate at the end of glycolysis, thus re-cycling the NAD. So, lactate must then be the end product of glycolysis if glycolysis is to continue.

2. If pyruvate is the important molecule that enters the mitochondia for further energy production, why would there be lactate shuttle systems embedded in the mitochondiral membrane? If lactate is the end product of glycolysis, there is no pyruvate available to enter the mitochondira. It appears that lactate is in fact shuttled in to the mitochondiral inner membrane space where it is converted back to pyruvate by lactate dehydrogenase and the rest we know. This seems to happen for the sole purpose of oxidizing those NADH's in the cytoplasm so glycolysis can continue. Now, if the lactate shuttles become saturated (i.e. high levels of lactate because glycolysis is going too fast. High intensity exercise for example) then excess lactate is shuttled out of the cell causing a rise in blood lactate levels.

3. Lactate is not a waste product. Actually, it is a source of energy, like glucose. Organs like the brain and heart love to use lactate and the liver converts excess blood lactate back to glycogen for storage and later use. Also, high lactate levels, in blood and muscle, after intense exercise typically return to resting levels within ~15 minutes of rest. So lactate is not a good candidate for causing delayed onset muscle soreness, which occurs 1-2 days after the exercise (there's another theory about that).

Essentially, we produce lactate ALL the time. It only becomes a problem when we produce it faster than we can use it.

A final note about lactic acid and lactate. The true end product of glycolysis is likely lactic acid. However, once formed, lactic acid quickly looses a hydrogen ion and becomes the salt lactate.

That's it in a nutshell. Anyone awake? <img src="/forums/images/graemlins/lol.gif" alt="" />

Clay, why the interest (of which I'm glad)? I though you, Phil and others didn't believe in science <img src="/forums/images/graemlins/cheers.gif" alt="" />

Without trying to pick another fight, and I'm taking a bit of a privilege lumping bretwalda here with me; It's not science we have a problem with. It's politically driven "science". As I said before, in this country, science (as we hear of it on the evening news) is politics and politics is (a) religion.

It's not that all science is BS, I just don't believe anything I hear on the news or in print.

Science... real, apolitical science, is tremendously interesting to me. I've always had a passion for chemistry and physics, as well as other physical sciences. And science of the body is really interesting.

While I understand that many real and beneficial discoveries have come about due to government funding of science, I believe that our government's involvement in science has taken a severely wrong turn. Their motives for involvement in science are no longer to be trusted.

I hope this clears things up.

Phil?

Clay, I never thought you picked fights. I haven't been offended by anything you've said, not that my offense would be your responsibility anyway <img src="/forums/images/graemlins/cheers.gif" alt="" />

I agree with much of what you said above. My view of your position on this issue has changed considerably. I also think that government involvement is science can be ethically questionable. However, I do think it's important to consider that problematic government involvement dependents on the type of science. I worked at a federally funded research institute for 6 years (NIEHS) and I can say that the science we did in the lab and the papers we published (still writing them) was not overseen or influenced by government agenda at all. I could have done whatever I liked and I did. But medical research will only serve to help the government and cost them less. It would be hard to make the situation worst for the government in that case. The other problem is if the government didn't spend millions and millions of dollars on medical research, who would pay for it? Yes, there are other sources of funding, but not in the same league as NIH.

Having said that, other science should be conducted independently of government. Climate research is one example of where the government could benefit greatly from censorship.

Whatever the government's motive for funding NIH is, while that money is spent for the greater good, I'm happy.

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