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<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>Bradley A. Young</dc:contributor>
  <dc:contributor>David A. Close</dc:contributor>
  <dc:contributor>Jesse Semeyn</dc:contributor>
  <dc:contributor>T. Craig Robinson</dc:contributor>
  <dc:contributor>Jennifer M. Bayer</dc:contributor>
  <dc:contributor>Weiming Li</dc:contributor>
  <dc:creator>Mara B. Bryan</dc:creator>
  <dc:date>2006</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;Recent studies have provided evidence that 15&amp;alpha;-hydroxytestosterone (15&amp;alpha;-T) and 15&amp;alpha;-hydroxyprogesterone (15&amp;alpha;-P) are produced in vitro and in vivo in adult male sea lampreys (&lt;/span&gt;&lt;i&gt;&lt;a class="linkText"&gt;Petromyzon&lt;/a&gt;marinus&lt;/i&gt;&lt;span&gt;), and that circulatory levels increase in response to injections with gonadotropin-releasing hormone (&lt;/span&gt;&lt;a class="linkText"&gt;GnRH&lt;/a&gt;&lt;span&gt;). We examined four species from the Petromyzontidae family including silver lampreys (&lt;/span&gt;&lt;i&gt;Ichthyomyzon unicuspis&lt;/i&gt;&lt;span&gt;), chestnut lampreys (&lt;/span&gt;&lt;i&gt;I. castaneus&lt;/i&gt;&lt;span&gt;), American brook lampreys (&lt;/span&gt;&lt;i&gt;Lethenteron appendix&lt;/i&gt;&lt;span&gt;), and Pacific lampreys (&lt;/span&gt;&lt;i&gt;Entosphenus tridentatus&lt;/i&gt;&lt;span&gt;) to determine if these unusual&amp;nbsp;&lt;/span&gt;&lt;a class="linkText"&gt;steroids&lt;/a&gt;&lt;span&gt;&amp;nbsp;were unique to sea lampreys or a common feature in lamprey species. In vitro production was examined through incubations of testis with tritiated precursors, and 15&amp;alpha;-T and 15&amp;alpha;-P production was confirmed in all species through co-elution with standards on both high performance&amp;nbsp;&lt;/span&gt;&lt;a class="linkText"&gt;liquid chromatography&lt;/a&gt;&lt;span&gt;&amp;nbsp;(&lt;/span&gt;&lt;a class="linkText"&gt;HPLC&lt;/a&gt;&lt;span&gt;) and thin layer&lt;/span&gt;&lt;a class="linkText"&gt;chromatography&lt;/a&gt;&lt;span&gt;. In vivo production was proven by demonstrating that HPLC-fractionated plasma had peaks of immunoreactive 15&amp;alpha;-T and 15&amp;alpha;-P that co-eluted with standards through using previously developed radioimmunoassays for 15&amp;alpha;-T and 15&amp;alpha;-P. The possible functionality of 15&amp;alpha;-T and 15&amp;alpha;-P was further examined in silver and Pacific lampreys by investigating the effect of injection of either type of lamprey GnRH on plasma concentrations of 15&amp;alpha;-T and 15&amp;alpha;-P. Injections with exogenous GnRH did not affect circulatory levels of either steroid in silver lampreys, and only&amp;nbsp;&lt;/span&gt;&lt;a class="linkText"&gt;GnRH&lt;/a&gt;&lt;span&gt;&amp;nbsp;III elicited higher levels of both steroids in Pacific lampreys. The 15&amp;alpha;-hydroxylase enzyme(s) for steroids appeared to present in adult males of all species examined, but the question of whether 15&amp;alpha;-hydroxylated&amp;nbsp;&lt;/span&gt;&lt;a class="linkText"&gt;steroids&lt;/a&gt;&lt;span&gt;&amp;nbsp;are functional in these lamprey species, and the significance of the 15-&lt;/span&gt;&lt;a class="linkText"&gt;hydroxyl&lt;/a&gt;&lt;span&gt;&amp;nbsp;group, requires further research.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1016/j.ygcen.2005.11.003</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Elsevier</dc:publisher>
  <dc:title>Comparison of synthesis of 15α-hydroxylated steroids in males of four North American lamprey species</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>