15 alpha-Hydroxytestosterone produced in vitro and in vivo in the sea lamprey, Petromyzon marinus.
Prior research has shown that the testes of lampreys are able to synthesize 15-hydroxylated steroid hormones in vitro. Here we show that testes of the sea lamprey Petromyzon marinus L. are able to convert tritiated testosterone into tritiated 15alpha-hydroxytestosterone (15alpha-T) in high yield. The identity of the tritiated 15alpha-T has been confirmed by: co-elution with standard 15alpha-T on high performance liquid chromatography (HPLC); co-elution on thin layer chromatography (TLC); co-elution of acetylated tritiated and standard 15alpha-T on TLC; and strong binding to an antiserum developed against 15alpha-T. The strong reaction between the tritiated 15alpha-T and the antiserum has been used to develop a radioimmunoassay (RIA). The RIA operates over the range of 500-2pg per tube; and can be applied directly to plasma samples. This assay has been used to demonstrate that 15alpha-T is present in blood plasma of the sea lamprey. The concentrations of 15alpha-T in captive lamprey were found to be as follows (pg/ml; mean+/-SEM, n): parasitic stage (reproductively immature), <20, n=7; pre-ovulatory females, 156+/-30, n=8; ovulated females, 62+/-9, n=5; pre-spermiating males, 275+/-19, n=8; spermiating males, 216+/-48, n=8. When spermiating male plasma was fractionated on HPLC, immunoreactivity was found exclusively in the expected elution position of 15alpha-T. The biological significance of this steroid has yet to be established.
Bryan
Mara B
MB
Department of Fisheries and Wildlife, Michigan State University, 13 Natural Resources Building, East Lansing, MI 48824-1222, USA.
Scott
Alexander P
AP
Cerný
Ivan
I
Seon Yun
Sang
S
Li
Weiming
W
D000818:Animals; D006915:Hydroxytestosterones / Q000032:analysis / Q000097:blood / Q000378:metabolism*; D066298:In Vitro Techniques; D007798:Lampreys / Q000378:metabolism*; D008297:Male; D011849:Radioactive Tracers; D011863:Radioimmunoassay / Q000379:methods; D013737:Testis / Q000378:metabolism*; D013739:Testosterone / Q000096:biosynthesis*
D006915:Hydroxytestosterones; D011849:Radioactive Tracers; D013739:Testosterone; C035390:15-hydroxytestosterone