Northern analysis of CD80 and bovine luteal tissue. A) Representative Northern blot of CD80 mRNA and corresponding G3PDH mRNA in luteal tissue samples collected early, during midcycle, or late in the estrous cycle, and at 0, 0.5, 1, 4, 12 or 24 hours following administration of PGF2α. Muscle tissue RNA served as a negative control, and lymph node RNA served as a positive control. B) Steady-state concentrations of CD80 mRNA in luteal tissue. Bars represent densitometric values of CD80 mRNA normalized to G3PDH mRNA detected by Northern analysis (n = 4 CL at each time point). Values with different letters tended to be different (p = 0.074).