Table 1. Effect of gestogens on the height of the vaginal
epithelium at various intervals after cessation
of treatment (height in am).

     

Treatment
Chlormadinone+ Control
mg/gilt/da (3 groups

e T P Ti2s T e ] o T Saabd
3 6 5 7 5
PRS2 TB5.8 S T A0LY 3.2
7 8 5 9 8 8
36.0 53.3 88.0  40.5 50.8 59.1
6 6 5 1 7 7
43.6 39.6 43.4 37.4 43.9 36.7

+ Kindly supplied by IBV, Lugano (progesterone)
and The Syntex Corporation, Palo Alto (CAP).

the changes in the height of the vaginal epithelium with high-
est levels in gilts treated with 112.5 mg progesterone and
slaughtered on day 8. While the PAS-positive reaction was con-
fined to the luminal zone of the vaginal epithelium, the alkal-
ine phosphatase occurred only in the basal portion. There was
little enzyme activity present on day 1, while on day 8, the
amount of this enzyme decreased with increasing hormone levels
from 2.7 to 1.2 units after progesterone treatment and from

2.7 to 2.3 units after CAP feeding.

n
¥
n
x

IIEIIII

-
U
Hl B

PDEISigTc 8- 81 0o n

These results indicate that, apart from the stimulating effect
of low doses of CAP on the vaginal epithelium, there are no
principal differences between the two hormones, as both induced
a dosage-dependent maximal proliferation on day 8 after end of
treatment, which coincided roughly with the ovulatory phase.
However, the synthetic gestogen, CAP, differed from the natural
hormone, progesterone, in its inefficiency to elicit a strong
rebound effect following the end of treatment. It is signifi-
cant that HAFEZ (1965) was unable to recover viable embryos
from CAP-treated sows, which indicates an unsuitable intrauter-
ine environment, since fertilization had taken place. With re-
gard to the proliferation of the vaginal epithelium by 1 mg CAP
it should be noted that the gilts of this treatment group show-
ed a high incidence oestrous symptoms at about 11 days after
initiation, i.e.well before end of treatment. This is evidence
that this compound even facilitates ocestrus and ovulation when
given in low doses. Since CAP has been claimed to be without
ocestrogenic activity (HARPER 1962), the stimulating effect on
the vaginal epithelium may have been channelled through the
hypothalamo-hypophyseal system.

 

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