THE UNIVERSITY OF MANITOBA STUDIES ON OVINE PLACINTAL ...

14r
Anal.vtical Sodi um Dodecyl Sql.fatê_ (SDS) pól vãcr.vl ámidS _cs.l (Sl ab)
Electróphore3iS an.d Molecular }Jeight DetenÍination
Fìgure l3 shows the eì ectropho reti c, mobiìity of the
purified oPL (A) in an analyt.ical SDS-polyacryl ami de gel (slab)
electrophoresis in comparison with other protein markers (S_hpL;
C-cytochrome C; D-Ribonuclease; E.trlyeglsbin; F-Ovine prolactin;
G- Ovalbumín '; H-chymotryps i n ogen A; J-Bovine serum albumin).
When the distance traveled by these prote.ins is pìotted
against the known molecular weight of the proteins as shown in
Figure '|4, it is apparent that the molecular we.ights of opL, hpl,
and oPRL are very sirnilar, : estimated betwöen. .
19,500 to 2l ,500.
Ditplu.ur.nt Cu.u.r of oPL in th. Rud i o".c.ptorur.uy fo. proluctin
(RRA-PRL) and for Growth Hormone (RRA:GH) usíng RabbJt Iissues
l,lhen the purified opl preparation vvas assayed in both the
RRA-PRL and RRA-GH (Figure l5 a and b respectivety), opl inhibited the
binding of either l25I-opnL o" l2SI-oGH in à parallel manner to the
homone standards used (opRL for RRA-pRL and oGH for RRA-GH respectively).
In the RRA-PRL, oPL has twice the potency of opRL. Whereas in the
RRA-GH, oPL is about equal potent with oGH,in cornpeting for
'GH-receptor sites. t^rhen the ratio of proiactin to growth hormone
activity of oPL was compared with that found for hGH and hpl by the
two rad i oreceptoras says , it ìs apparent that opl and hGH have a ratio
of 2:1, whereas hPL has a ratio of '100:ì.