Effects of litter and male on corpora lutea of the postpartum Mongolian gerbil.

Abstract

The effects of litter and male on postpartum formation and maintenance of the corpora lutea (CL) were studied in 48 Mongolian gerbils. Postpartum estrus was determined by vaginal smear and occurred 12 to 24 hr. after parturition. All 48 females had a postpartum ovulation. Sequential laparotomies (every 4 days for 26 days after the postpartum estrus) showed that complete morphological regression of CL did not occur within 26 days for any of the females in which the litter was present, whether the male was intact, vasectomized or removed. In the absence of a litter the morphological lifespan for CL when the male was present (intact or vasectomized) averaged > 13.5 and 14.3 days, respectively, whereas removal of the male resulted in rapid CL regression (8.8 days; treatment effect, P<.005). The interval from first to second postpartum estrus in litter-removed groups was shorter in the male intact group (8.5 days; male vasectomized, 12.4 days; male removed, >15.5 days; treatment effect P<.025). Also a second ovulation occurred in many of the females from the litter-removed groups (male intact, six of eight; male vasectomized, seven of eight; male removed, three of eight).