THE UNIVERSITY OF MANITOBA STUDIES ON OVINE PLACINTAL ...

165
D. STUDIES ON THE SECRETION OF OPL DURING PREGNANCY
Prêgri¿iricy
Ithternal ¡irid Fetiil Cônceritr¿iil ôn s - nf npl
Figure 25 shows the concentration of p,lasma opL in ìl
pregnant ewes at varlous stages of pregnancy up to l4l days of
gestation. Parturitìon occurred at day ì4.l_ì50. After day 48, opl
concentrations were greater than 2 ng/mr and increased as pregnancy advanced
to peak ievels on day l3'l-.l4t. The increased variability at day l4i
no doubt reflects the drfferences in the fime at whìch the preparturition
drop commences.
After the initial peak of opl at day 131_l4l , there was
generally a declJne ln pL concentratJon commenclng approxlmateìy S days
before parturition as,shown in Flgure 26. In the postpartum period,
oPL levels decreased rapfdly.
Preqnancv
FÍgure 27 depicts the pattern of opL detected in uterine
vein blood and ln peripheral blood. By day 25, opL was detectab.le
in uterine vein blood of sor¡e animals. In this study, it was found
that oPL leveìs in uterine blood were consistenily higher than those
in the peripheral blood in the same ewe.