Endometrial expression of IL1A, IL1B and IL1R2. Expression of mRNA encoding IL1A, IL1B and IL1R2 in endometrial biopsies collected from infertile (closed bar) and fertile animals (open bar), during Periods 1 and 2. RNA was isolated from biopsies, reverse transcribed and analysed by quantitative PCR for the mRNA encoding the pro-inflammatory cytokine isoforms IL1A and IL1B and corresponding receptor, IL1R2. *P < 0.05 compared with infertile animals, within the Period. Numerical values are presented as the mean + SEM.