Figure 2. Expression of progesterone receptors in corneal tissues following ovariohysterectomy. A: PR mRNA levels in corneal tissues of skeletally mature animals following OVX: A cohort of skeletally mature 54-week-old female rabbits were either left unoperated (controls) or were subject to OVX. After 8 weeks, the cornea was collected from these animals and separated into central and peripheral corneal tissue using a 6 mm biopsy punch. mRNA levels of PR were determined by RT–PCR in these tissues. Values are plotted as a percentage of PR mRNA levels in normal control tissues. Significant changes compared with normal controls are indicated (p<=0.05, p=NS). B: Maturation associated changes in PR levels of corneal tissues: Corneal tissues were collected from rabbits at 6, 22, and 32 weeks of age and separated into central and peripheral corneal tissues using a 6 mm biopsy punch. Levels of PR mRNA were determined by RT–PCR in these tissues. Values are plotted as a percentage of PR mRNA levels in 6 week old animals. Significant changes in PR levels compared with the 6 weeks old animals are indicated (p<=0.05, p=NS). C and D: Influence of pre-pubertal OVX on PR mRNA levels in corneal tissues: Eight week old rabbits underwent OVX surgery or were left unoperated to act as controls until 22 and 32 weeks of age. As described in the Methods section, corneal tissues were collected from these 22 and 32 week old animals and mRNA levels for PR were determined by RT–PCR. Values are plotted as a percentage of PR mRNA levels in normal control animals. Significant changes compared with normal controls are indicated. (p<=0.05, p=not significant [NS]).