THE UNIVERSITY OF MANITOBA STUDIES ON OVINE PLACINTAL ...

SFCT.IoN II : pl.scussr0N
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The reasons that I empl oyed ,only RRA-cfl to monitor the
hormonal activity of ovine placental lactogen during purif,ication
were several : l. lle had previousìy shown that growth hormone-
like and prolactin-tike activities resided ín the
molecule of opl (Chan et at ,ì976); 2, The ieproducìbilit.y of
the RRA-GH is higher than RRA-pRL(90% compared to 65% reproducíbility);
3.. l25t-neu is more stable than l2sl-opnL , during storage at _20 c.
and 4. The availabiìity of rabbit liver in our laboratory
is better than the aval'lability of rabbit marrmary gland.
Extraction and purÍ fì cati on
aCIl
In our initial attempts to purify opl from frozen placental
cotyledons, varlous difficu'lties were encountered. In the primary
extraction procedure, the alkaline extract was turb.id and viscous
and could not readily be cìeared by centrlfugaüon or filtration.
The viscosity of early-tenn placental extracts (S4_65 days) was
greater than that of extracts obtained from near term (l 30 -l4S days)