Our data reveal a significant increase in uterine expression of LIF mRNA and protein in the glandular and luminal epithelium that is temporally correlated with cessation of embryonic diapause and resumption of blastocyst development. The relative lack of detectable LIF protein in the endometrium during embryonic diapause is consistent with our detection of very low concentrations of LIF mRNA by PCR and our inability to detect LIF mRNA by in situ hybridization at that time. Failure to localize LIF transcripts in the myometrium at any stage of pregnancy conflicts with our consistent detection of LIF protein in the myometrium. This suggests that the polyclonal antibody to rhLIF cross-reacts with an epitope of another protein in smooth muscle. The same antibody reportedly detects LIF protein in the myometrium of rabbits. birth control yasmin
The earliest indicators of renewed embryonic development in the skunk are increased uterine weight and increased blastocyst diameter. The rapid and marked change in uterine weight was clearly evident even in the uterine sample containing embryos earliest in activation; weight of the paired uterine cornua from this animal was 2.4 times greater than the mean uterine weight during embryonic diapause. Changes in blastocyst diameter occur slowly over the several days of embryo activation.