THE UNIVERSITY OF MANITOBA STUDIES ON OVINE PLACINTAL ...

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(c) Imnunologicaì Properties of opL:
Handwerger et al('1974) reported that opl-antiserum
cross-reacts with ovine growth hormone but there is no cross-reaction
with human placenta'l ìactogen, hunan prolactin" human growth hormone,
and or ovlne prolactin by 0uchterlony diffusion method. In subsequent
studies by the same group (Handwerger et a.l ,1gl7l , they acknowìeged
that their previous observations may be erroneous, and confirmed that
oPl-antiserum.does not cross-react with any homone preparations.
(d) Secretjon and Distribution of opl neasured by RIA:
Handwerger et a] (1977) reported that by RIA, opL was
first detected in the maternar prasma at 4ì-50 days of gestation and
reached a peak concentration of .l.5 to 2.5 ug/ml at l2l-.l3t days of
gestation. The oPL concentratiôn ln plasma was 336 nglml and in
allantoic fluld was 29 ng/m1. After surgical removal of the placenta,
oPL disappeared from maternal plasma wlth a half-llfe of 29 minutes.
(e) Biological Effects:
oPL is a potent lactogen which stimulates lactat.lon
Ín vivo in the rabbit and mouse mamnary gland explants (Handwerger
et al ,1974; Martal et al ,l97b; Chan et al ,1976) and also is a potent
growth promoting protein as demonstrated in hypophysectomi zed rats
(Handwerger et al ,.l974; Chan et al,t976).
Handwerger et al(1925) lnJected partlalìJ purifled
oPL into fasted pregnant and non-pregnant ewes and found that.lntra_