Influence of estrogens on peroxidase activity in the Syrian hamster liver, kidney, and renal adenocarcinoma.

Only very low levels of peroxidase activity were detected in castrated male hamster kidneys [1.0 +/- 0.8(S.E.) units/g protein], and chronic estrogen administration, either diethylstilbestrol (DES) or 17 beta-estradiol, for 1-5 months did not result in any appreciable increase in this activity. In contrast, hamster liver peroxidase activity was initially 10- to 20-fold higher than kidney levels, and chronic estrogen treatment for similar periods resulted in up to a 9-fold elevation in the activity of this enzyme. Moreover, the level of liver peroxidase activity in both intact and in 5 alpha-dihydrotestosterone-treated castrate hamsters was 2-fold higher than castrate-untreated values. Pure renal carcinoma induced after 9 months of estrogen treatment exhibited peroxidase values similar to those found in hamster livers [124 +/- 27 (S.E.) units/g protein] following estrogen treatment. When administered concomitantly with DES, tamoxifen significantly reduced the elevated levels of liver peroxidase activity observed after 2 months of DES treatment alone. A high affinity (KA = 0.10 X 10(9)M-1) estrogen receptor was found in liver cytosols of DES-treated hamsters which had increased slightly from untreated castrate levels.