Effect of a Intrauterine Foreign Body During the Estrous Cycle on Plasma Progesterone in Guinea Pigs 1

Summary

The progesterone concentration in peripheral plasma of sham-operated guinea pigs increased significantly during the estrous cycle from a nondetectable concentration at estrus to a maximum concentration on day 10, followed by a rapid decline. In the presence of an IUFB in both uterine horns, the progesterone concentration did not increase after day 4 of the cycle. Over the next 8 days, a slow decline in concentration occurred. The length of the estrous cycle was significantly shorter in animals having IUFB than in sham-operated animals.