Effects of OK-432 (Picibanil) on estrogen receptor levels and tamoxifen treatment in 7,12-dimethylbenz[a]anthracene-induced rat mammary cancers.
The effects of OK-432 (Picibanil) on estrogen receptor (ER) levels and subsequent tamoxifen (TAM) treatment were examined in 189 female Sprague-Dawley rats with 7,12-dimethylbenz[a]anthracene (DMBA)-induced mammary cancers. When OK-432 was administered (0.1 KE/kg i.p. once weekly) for 12 weeks to the rats after DMBA, the average ER level of the TAM-responsive tumors in the OK-432-treated group was significantly higher than that in the control group. The antitumor effect of TAM was significantly greater in the OK-432-treated group. When OK-432 was administered to rats with established DMBA tumors, the average ER levels did not change significantly after 2 or 4 weeks of treatment. ER levels in the control group (no treatment) fell significantly after 2 or 4 weeks. These results suggest that hormone dependence of DMBA-induced rat mammary cancers may be maintained or augmented by the administration of OK-432.
Iino
Y
Y
Department of Surgery, Gunma University School of Medicine, Maebashi, Japan.
Ogawa
T
T
Yoshida
M
M
Izuo
M
M
Takikawa
H
H
D015127:9,10-Dimethyl-1,2-benzanthracene; D000818:Animals; D001688:Biological Products / Q000494:pharmacology*; D005260:Female; D008325:Mammary Neoplasms, Experimental / Q000032:analysis* / Q000139:chemically induced; D010844:Picibanil / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011960:Receptors, Estrogen / Q000032:analysis* / Q000187:drug effects; D013629:Tamoxifen / Q000494:pharmacology*
D001688:Biological Products; D011960:Receptors, Estrogen; D013629:Tamoxifen; D010844:Picibanil; D015127:9,10-Dimethyl-1,2-benzanthracene