Interleukin-1 alpha in the rabbit uterus during early pregnancy.

: Immunoreactive (ir) interleukin-1 alpha (IL-alpha) was present in the endometrium and myometrium of the rabbit uterus during early pregnancy. Interleukin-1 alpha was at a high level in endometrial epithelium from days 3 to 6 of pregnancy. A similar level of IL-1 alpha was detected on day 6 of pseudopregnancy. Interleukin-1 alpha declined rapidly on day 7 at both the implantation and non-implantation areas. Our results suggest that IL-1 alpha may play a role in rabbit blastocyst implantation.