Reduced fertility in females of the hereditary polydactyly rat.

The present studies assessed reproductive capacity of hereditary polydactyly(pd/pd) female rats that had genetically caused polydactyly in both fore- and hindlimbs. During an 8- or 10-day period of vaginal estrous cycle observation, persistent estrus was found in 30 to 39% of the pd/pd females. Although mating indices were comparable between polydactylous (pd/pd) and phenotypically normal (pd/+ or +/+) females, fertility indices were significantly decreased in pd/pd females. All impregnated pd/pd females delivered normally but had a significant decrease in the numbers of corpora lutea and pups delivered as compared with pd/+ or +/+ females. Examination of oviductal ova at 2 days after copulation revealed ovulation in only 75% of the pd/pd females and also a slight decrease in the numbers of ovulatory corpora lutea and oviductal ova in these females. In the nonovulating persistent estrus pd/pd females, the ovaries were polycystic. These results demonstrate a reduction in reproductive ability of pd/pd females.