THE UNIVERSITY OF MANITOBA STUDIES ON OVINE PLACINTAL ...

146
l,lhen human liver membrane prepara ons were used for thê
rad'loreceptora ssay as shown in Flgure 16, the purlfied opl preparation
was twice as potent ashcHin inhlblting the binding of l25I_opL,
whereas non-primate GH preparati ons ( oGH an' bGH. not shown) faiìed to inhibit
even at concentration(.l0 uglml). Similarly,ovine proìactin also was without
effect in the àssay. In this assay hpL caused a slight inhibition only
at concentratjons in excess of 1,000 nglml and hence, it,s cross-
reaction in this assay ls less than ll|. These resuìts (data from
Figure 15 and 16) suggest a close structural homology between opl
and primate GH.