Combined and sequential treatment using FCE 21336, a new prolactin-lowering drug, and medroxyprogesterone acetate (MPA) in DMBA-induced tumors in rats.
The effect of the new, prolactin-lowering ergoline derivative FCE21336 and medroxyprogesterone acetate (MPA) given alone and in combination was tested on DMBA-induced mammary tumors in rats. FCE 21336 (0.05 and 0.4 mg/kg p.o.) and MPA (25 and 50 mg/kg s.c.), administered 5 days/week for 4 weeks, inhibited the growth of established tumors and reduced serum prolactin levels. Combined treatment inhibited tumor growth more than single treatment. These results were confirmed in a second experiment: the antitumor effect of the combination of FCE 21336 (0.1 mg/kg p.o.) and MPA (50 mg/kg s.c.) was greater than that of the single treatment and was similar to the effect of ovariectomy. In this experiment rats with tumors that did not respond to 4 weeks' treatment with FCE 21336 (0.1 mg/kg p.o.) were treated during the next 4 weeks with MPA (50 mg/kg s.c.). MPA was effective on FCE 21336-unresponsive tumors. These data indicate that combined FCE 21336 and MPA treatment is more effective than single treatment and that MPA is effective on tumors not sensitive to the prolactin-lowering drug.
D015127:9,10-Dimethyl-1,2-benzanthracene; D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D002369:Castration; D005260:Female; D008325:Mammary Neoplasms, Experimental / Q000097:blood / Q000139:chemically induced / Q000188:drug therapy*; D008525:Medroxyprogesterone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use; D017258:Medroxyprogesterone Acetate; D011388:Prolactin / Q000097:blood; D051381:Rats; D011919:Rats, Inbred Strains
D000970:Antineoplastic Agents; D015127:9,10-Dimethyl-1,2-benzanthracene; D011388:Prolactin; D017258:Medroxyprogesterone Acetate; D008525:Medroxyprogesterone