Gelatinase mRNA expression during gestation as analyzed by quantitative PCR. The expression values were normalized with cloned MMP-2 and MMP-9 as standards. Expression refers to the mean +/- SD. Two cows were used on each day during the estrous cycle, and three cows were used on each day during gestation. The abbreviations are the same as in Figure 1. A: MMP-2 in endometrium. B: MMP-9 in endometrium. C: MMP-2 in fetal side tissues. D: MMP-9 in fetal side tissues. a-c:abc; a-d: a, b, c, d; a-e: a, b, c, d, e; a-f: a, b, c, d, e, f; b-f: b, c, d, e, f; c-f: c, d, e, f; d-f: d, e, f. Different letters above each bar indicate significant difference at P < 0.05. No significant difference was found in Figures 2B, 2C and 2D.