THE UNIVERSITY OF MANITOBA STUDIES ON OVINE PLACINTAL ...

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Figure 35 deplcts a typlcal standard curve for progesterone
ln the competitive protein-binding assay using dog pìasma. ïhe lowest
amount of progesterone measured by this system was 0.ì nanogram of
progesterone.
The relatÍonships between plasma ìevels of opRL and oGH durÍng
pregnancy is shown in Figure 36A, whereas the rerationshrps between
oPL and progesterone concentration is shown in Figure 368. The honnone
concentrations were measured in t pregnant ewes at varrous stages of
pregnancy up to l4l days of gestation. parturltion occurred at day .l4l_
'150. It is apparent that oGH levelswere not elevated significantly
throughout pregnancy' and the secreilon pattern of pracentar ractogen
was sÍmiìar to progesterone. Furthennore, Ít ís evrdent that the
concentrations of oPRL during pregnancy were inversely related.
to the levels of placental lactogen and progesterone.