THE UNIVERSITY OF MANITOBA STUDIES ON OVINE PLACINTAL ...

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Orilet Perissodactyla (Horse an¿l Asses):
There is no evidence to indicate the existence
of horse placental lactogen. In my own studies, I could
not find any cross-reactivity betîreen horse placental
extracts and ovine placental lactogen in the radioreceptor-
assay for placental Lactogen using sheep liver as receptors.
Order Artiodactyla (píg, camel, 'l 1ama, cow, goat, sheep, deer):
This order is actuall_y divided into three suborders,
the Suiformes (pig), the Tylopoda (camel and ìLama) and the
Ruminantia (cow, goat, sheep and the deer).
BecaÌ¡se most of the informatíon accu¡t¡ulateil in
recent years is concerned, with placental lactogens in the
covr, goat, and the sheep, therefore, I would like to
confine my discussion to these three spsçj95.
(i) cow:
Gusdon et al (19?O) are the first to report the
possibility of bPL in bovine placenta. They
demonstrated that the ext,racts of term bovine placental
extracts cross-reacted $rith ant,i-hpL serum. Later, using
co-culture of fragments of cotyledons with mouse ma¡nmary
gland explants, Forsyth and co-workers (Forsyth and Butt.Ier
1972t Forsyth, 1973; Buttle and Forsyth, L976]' demonstrated
that. placent.al lactogen is secreted in cows on days 36,
]-78, L82 and 270 of pregnancy. Bovine placental Lactogen
originated from fetal cotylédon and showed no detectable