Uterine receptivity to the artificial deciduogenic agent, concanavalin A, in pseudopregnant QS mice

The present study was undertaken to define the 'window' of uterine receptivity in the Quackenbush Special (QS) mouse as gauged by the capacity of the uterus to mount a decidual cell reaction (DCR) in response to the lectin Concanavalin A (Con A). Con A failed to induce a DCR when administered into the uterine lumen on Day 3 of pseudopregnancy (Day 1, copulatory plug). However, it was partially effective between 0600 hours and 0900 hours on Day 4, totally effective between 1200 hours on Day 4 and 1500 hours on Day 5, and virtually ineffective from this time onwards. When uteri were examined at specific time intervals after stimulation with the lectin at 1200 hours on either Day 4 or Day 5, uterine weights were significantly greater in animals stimulated on Day 5. The greatest rate of uterine growth began on Day 6 irrespective of whether Con A was administered on Day 4 or Day 5. Animals stimulated on Day 5 of pseudopregnancy produced a significantly larger oedema response and an earlier vascular permeability response than those stimulated on Day 4. The results indicate that: (i) Con A is deciduogenic in pseudopregnant QS mice; (ii) uterine receptivity in these animals spans a minimum period of 27 h beginning at midday on Day 4 of pseudopregnancy; and (iii) the uterus displays different patterns of growth, oedema, and vascular permeability following stimulation at different times during the receptive period.