THE UNIVERSITY OF MANITOBA STUDIES ON OVINE PLACINTAL ...

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Order Carniyora (dog, fox, cat, mirtk anii fêtrêt):
. Dogs are dependent upon the ovary for the mainÈenance
of pregnancy f,or ¡nost., if not ¿f] , of gestation. Sokolot¡ski
(L971) found that ovaríectomy in the dog as late as day
56 postbreeding resulÈed in premature termination of gestat,ion
(gestationaL period is 59-68 days). An enhancement of
lut,eal- function has been reported for the pregnant dog
as compared to Èhe non-pregnant dog beginning at about, 1.5
days post-ovulation (Smith et al, ]-974'). The increase in
progesterone secretion suggests the possibility of a
placental Luteotropin as implantation begiris at about this
time (Holst et al, 1971). Other r^rorkers, hovrever, have
not found an ênhancement of luteal activity in the pregnant
dog (Concannon et aI, 1925; Hadley, f9?5).
Using a haemagglutinin-inhibítion method, Gudson
et al (1970) reporÈed that there night be a placental
lactogen in Èhe dog placenta vrhich cross-reacts iriununologicaLly
with hPL. In our own studies (Kelly et aI, 1976) we f.ound
that dog pLacental extract, cross-reacted in the radioreceptor-
assay for prolactin using rabbit man¡nary gland as receptors
(xel-l-y et al , 1976) and in the radioreceptorassay for
placental lacÈogen using sheep Liver as receptors.
our claims.
mink and ferret.
Hor,rever, further studies are required to subst,antiate
vüe have not yet examined ùhe placentas of cat, fox,