Vie CONG. INTERN. REPROD. ANIM. INSEM. ARTIF., PARIS, 1968, VOL. II

EFFECTS OF PROGESTERONE AND CHLORMADINONE ON HISTOLOGICAL
CHARACTERISTICS OF THE VAGINAL EPITHELIUM OF YOUNG GILTS

J. Steinbach and D. Smidt
Institut fir Tierzucht, Universitat Gottingen, Germany

SUMMARY, Histologic and histochemical observations on the va-
ginal epithelium of progesterone- and CAP-treated gilts demon-
strated a strong dosage-dependent rebound effect following the
treatment with progesterone eight days after cessation of treat-
ment. CAP did not elicit an equally high rebound effect.

RESUME. L'étude histologique et histochimique de 1'épithéle
vaginal de jeunes truies traitées avec progesterone et CAP a
montré un 'rebound effect' prononcé huit jours aprés la fin

du traltement avec progesterone. CAP n'a pas causé un 're-

bound effect' d'une intensité semblable.

Frequently, the fertility of sows was greatly reduced after
oestrous cycle synchronization, and the high incidence of fol-
licular cysts, espécially after oral administration of synthe -
tic gestogens, has been attributed to an endocrine imbalance.
If this is the case, these endocrine disturbances should be-
come apparent in the functional structure of hormone-regulated
tissues in the genital tract.

Methods

Of 21 groups of gilts, 18 were randomly allotted to the treat-
ments of a 2 x 3 x 3 factorial design, while the 3 remaining
groups served as controls. The treatments and the distribution
of animals can be seen in Table 1. Tissue sections of the va-
ginae of all animals were fixed and stained for polysacchari-
des (PAS and Best's Carmin) and alkaline phosphatase. The in-
tensity of these staining results was scored subjectively, and
the total height of the vaginal epithelium was measured as a
criterion of endocrine activity.

Resul+t s

Table 1 and Figure I show that the proliferation of the vagi-
nal epithelium was most pronounced on day 8 after the end of
the hormone treatment. This effect was clearly dosage-depend-
ent, and although present in both, progesterone- and CAP-
treated animals, the rebound phenomenon was much stronger af-
ter treatment with the natural gestogen, progesterone. There
was evidence of a dosage-dependent depression immediately af-
ter the treatment with progesterone was stopped, while no such
effect became apparent after treatment with CAP. In fact,
there was even a stimulation of the vaginal epithelium of the
gilts which were fed 1 mg CAP and were slaughtered one day af-
ter the end of this treatment. Figure II shows that the in-
tensity of the carmin reaction is a reflection of the epithe-
lial height, lowest levels of glycogen being observed on day 8
after end of treatment. The PAS-positive material followed

1527