Semi-quantitative (sq) RT-PCR results (mean ± SEM; n=3–4 per group) for TNF-α (Panel A) and TNF- β (Panel B) mRNA in the macaque CL during the early (ECL, day 3–5), mid (MCL, day 7–8), mid-late (MLCL, day 10–12), late (LCL, day 14–16) and very-late (VLCL, day 17–19) luteal phase. Values were standardized to their respective cyclophilin control values. Different letters a,b represent significant differences (p<0.05) in TNF mRNA levels between stages of the luteal phase.