The deciduomal response to uterine trauma in pesudopregnant hamsters has been studied. Trauma was effected in one uterine horn by leaving a sterile silk thread in the lumen, pulling a thread through the lumen, injecting oil or air into the lumen or crushing the horn with a hemostat. At autopsy the traumatized and untraumatized horns were weighed separately and examined histologically for a deciduomal reaction. The day of greatest uterine sensitivity was found to be day 4 of pseudopregnancy, and maximal deciduomal growth (mean uterine weight ± S.E. = 2582 ± 279 mg) occurred by day 8. No significant further increase in uterine weight was seen by day 9, and by day 10 separation of the deciduoma from the myometrium had begun. Leaving a thread in the uterine lumen produced a significantly greater uterine weight by day 8 than with any other stimulus, but good deciduomal responses (uterine weights of 1679 ± 245, 1255 ± 156 and 1192 ± 219 mg) were induced by oil injection, pulling a thead through the uterus and crushing the uterus respectively. A poor reponse was produced by air injection. At no particular time during day 4 of pseudopregnancy was it possible to demonstrate a peak of uterine sensitivity using as a traumatic stimulus either oil injection or pulling a thread through the lumen. In this respect hamsters differ from both rats and mice, which have well defined peaks of maximal uterine sensitivity. Copyright © 1969 Wiley‐Liss, Inc.
