THE UNIVERSITY OF MANITOBA STUDIES ON OVINE PLACINTAL ...

l. Súrglcat Method
't77
Figure 3l shows the half_tinre dlsappearance rate of opL
from maternar prasma after surgical removar of the uterus . The
half-time disappearance rate of opL calculated from the three
ewes {s approx.imate'ly 50 to 57 minutes.
2. Injection Method
The harf-time disappearance rate of radio-iodJnated opl
(1251-opl-) from the circulation of pregnant ewes is shown in Figure 32.
A biphasic exponential curve was obtained by plotting the ìogarithm
of the radioactivlty in the TCA -preci pi tabl e material against, time. Two estimates
for half_time of the decay of radioactivlty were denoted t+(S) and
tå(L), the values of which were r.3 to r.7 minutes and 50 to 65 mrnutes
respecti vely.
The harf-time disappearance rates of opL carcurated from the
samples of whoìe b100d did not differ markedry from the varues obtained
from the TCA-prec i pi tabl e materia'l
The ratio of the radioacilvlty found in various organs to
that of blood samples taken from aninals whÍch were killed at 4 h is
sunmarized in Table vII. At 4 h the organ to bìood ratro found for a'
tlssues remained below 1.0 wlth exceptlon of kidney whlch has a ratïo
of l0 or more. This study suggests that the kidney may be degradation ,
site for opl in the sheep.