THE UNIVERSITY OF MANITOBA STUDIES ON OVINE PLACINTAL ...

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samples, signif,icant elevations were noted 24 to 4g hours
after the appearance of mCG in serum. These findings
suggested that the attachlng blastocyst or thê developing
syncytiotrophobLast possesses or rapidly attains the capacity
to secrete mcc. The presence of mcc at the tine of inpJ-ant_
ation probably maintains the viability of the corpus luteum
and temporarily enhances progesterone sêcretion irnrnediately
following implantation. Similarly, using this RIA, Hodgen
et al (1975) al-so quantitated the chorionic Aonadotropin
production by the placenta of the rhesus monkey. They found
that mCG was detected in extracts of rhesus monkey placentas
as early as 22 days after fertilization, but Íras not detect-
abl-e in the placenta after 40 days of gestation.
More recently, WaLsh et, al (1922) again measured
plasma nCG from pregnant monkeys at.22,42 and 15? days of
gestatíon using ovine LH as standard. They found that
the l-evels of mCG at day 22 of pregnancy \4rere approximatêly
25O ng/mli however, during the lattêr stages of gestation
mCG r¡rere either nondetectable or less than 0.7 ng/ml. Thus¡
their findings confirm the results of Hodgen et al (1974).
No inforrÌÌation exists on the fact,ors which
regulate the synthesís and secretion of mcc.