Receptor concentrations for estradiol and progesterone in surgically induced endometriosis in the rat.

In order to obtain more detailed information about the validity of the rat as an endometriotic experimental model, endometriosis was surgically induced in 48 female Wistar rats, and the estrogen (ERc) and progesterone (PRc) receptor concentrations present in experimental endometriosis and endometrium were compared in the four estrous phases (n = 12). Lower values of ERc were found in endometriosis than in endometrium (proestrus, 156.27 +/- 24.09 vs. 195.27 +/- 32.13 pmol/g tissue, P < 0.05; estrus, 302.33 +/- 45.16 vs. 335.67 +/- 44.82 pmol/g tissue, P < 0.05; metestrus, 166.60 +/- 26.09 vs. 193.30 +/- 22.04 pmol/g tissue, P < 0.05; diestrus, 130.27 +/- 20.58 vs. 135.81 +/- 16.25 pmol/g tissue, P > 0.05; Student's t-test). As in the case of ERc, lower PRc were observed in endometriotic than in endometrial tissues (proestrus, (proestrus, 137.83 +/- 22.64 vs. 176.54 +/- 21.78 pmol/g tissue, P < 0.05; estrus, 242.10 +/- 34.78 vs. 286.20 +/- 31.74 pmol/g tissue, P < 0.05; metestrus, 194.36 +/- 35.08 vs. 224.73 +/- 20.21 pmol/g tissue, P < 0.05; diestrus, 147.72 +/- 26.21 vs. 147.33 +/- 22.65 pmol/g tissue, P > 0.05; Student's t-test). Similar ERc/PRc ratios were found for both the endometriotic and the endometrial tissues (proestrus, 1.14 +/- 0.07 vs. 1.08 +/- 0.09, P > 0.05; estrus, 1.29 +/- 0.19 vs. 1.21 +/- 0.18, P > 0.05; metestrus, 0.87 +/- 0.14 vs. 0.89 +/- 0.11 P > 0.05; diestrus, diestrus, 0.89 +/- 0.06 vs. 0.92 +/- 0.06, P > 0.05; Student's t-test, NS).(ABSTRACT TRUNCATED AT 250 WORDS)