Hydrogen Peroxide
<p>Hydrogen peroxide is also one of the two chief chemicals in the defense system of the <a href="http://en.wikipedia.org/wiki/Bombardier_beetle" title="Bombardier beetle">bombardier beetle</a>, reacting with <a href="http://en.wikipedia.org/wiki/Hydroquinone" title="Hydroquinone">hydroquinone</a> to discourage predators.</p>
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A study published in <i><a href="http://en.wikipedia.org/wiki/Nature_%28journal%29" title="Nature (journal)">Nature</a></i> found that hydrogen peroxide plays a role in the <a href="http://en.wikipedia.org/wiki/Immune_system" title="Immune system">immune system</a>.</p>
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Scientists found that hydrogen peroxide inside of cells increased after tissues are damaged in <a href="http://en.wikipedia.org/wiki/Zebra_fish" title="Zebra fish" class="mw-redirect">zebra fish</a>, which is thought to act as a signal to <a href="http://en.wikipedia.org/wiki/White_blood_cell" title="White blood cell">white blood cells</a> to converge on the site and initiate the healing process. When the genes required to produce hydrogen peroxide were disabled, white blood cells did not accumulate at the site of damage. The experiments were conducted on fish; however, because fish are genetically similar to humans, the same process is speculated to occur in humans. The study in <i>Nature</i> suggested <a href="http://en.wikipedia.org/wiki/Asthma" title="Asthma">asthma</a> sufferers have higher levels of hydrogen peroxide in their lungs than healthy people, which could explain why asthma sufferers have inappropriate levels of white blood cells in their lungs.<sup id="cite_ref-BBC_24-0" class="reference"><a href="http://en.wikipedia.org/wiki/Hydrogen_peroxide#cite_note-BBC-24">[25]</a></sup><sup id="cite_ref-Nature_zebra_25-0" class="reference"><a href="http://en.wikipedia.org/wiki/Hydrogen_peroxide#cite_note-Nature_zebra-25">[26]</a></sup></p>
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Hydrogen peroxide has important roles as a signaling molecule in the regulation of a variety of biological processes.<sup id="cite_ref-26" class="reference"><a href="http://en.wikipedia.org/wiki/Hydrogen_peroxide#cite_note-26">[27]</a></sup> Hydrogen peroxide also plays an important role in aging<sup id="cite_ref-27" class="reference"><a href="http://en.wikipedia.org/wiki/Hydrogen_peroxide#cite_note-27">[28]</a></sup> and cancer.<sup id="cite_ref-28" class="reference"><a href="http://en.wikipedia.org/wiki/Hydrogen_peroxide#cite_note-28">[29]</a></sup></p>
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The amount of hydrogen peroxide in biological systems can be assayed using a fluorimetric assay.<sup id="cite_ref-pmid8074285_29-0" class="reference"><a href="http://en.wikipedia.org/wiki/Hydrogen_peroxide#cite_note-pmid8074285-29">[30]</a></sup></p>