Adrenal steroids stimulate growth and progesterone receptor levels in rat uterus and DMBA-induced mammary tumors.

We have studied the effect of treatment with the adrenal steroids androst-5-ene-3 beta,17 beta-diol (delta 5-diol) and dehydroepiandrosterone (DHEA) on the growth and progesterone receptor levels of dimethylbenz(a)anthracene (DMBA)-induced mammary tumors in the rat. While the total number of tumors in ovariectomized animals was 0.60 +/- 0.19 tumor per rat after 24 days, it increased to 2.54 +/- 0.50 (p less than 0.01) and 1.42 +/- 0.26 (p less than 0.01) in the delta 5-diol and DHEA (2 mg, twice daily) treated animals, respectively. While very few new tumors developed during a 24-day period in ovariectomized animals (0.07 +/- 0.07/rat), an average of 0.47 +/- 0.19 (p less than 0.05) new tumor per animal appeared in intact rats. In ovariectomized animals treated with delta 5-diol or DHEA, the numbers of new tumors were 0.77 +/- 0.26 (p less than 0.05) and 0.42 +/- 0.15 (p less than 0.05), respectively. An even more striking effect was observed on average total tumor area, which decreased from 4.70 +/- 0.95 cm2 in intact animals to 0.75 +/- 0.27 cm2 (p less than 0.01) following ovariectomy. Values of 9.79 +/- 2.25 (p less than 0.01) and 3.93 +/- 0.86 cm2 (p less than 0.01) were found in the delta 5-diol- and DHEA-treated ovariectomized animals, respectively. Treatment of ovariectomized animals with delta 5-diol and DHEA caused a marked increase (p less than 0.01) in progesterone receptor levels in both the uteri and DMBA-induced mammary tumors. Uterine weight was also stimulated (p less than 0.01) by treatment with the two adrenal steroids