4-Aminoandrostenedione derivatives: a novel class of irreversible aromatase inhibitors. Comparison with FCE 24304 and 4-hydroxyandrostenedione.
FCE 24928 (4-aminoandrosta-1,4,6-triene-3,17-dione) was selected among a series of 4-aminoandrostenedione derivatives as a novel irreversible aromatase inhibitor. Its in vitro and in vivo properties have been studied and compared to FCE 24304 (6-methylenandrosta-1,4-diene-3,17-dione) and 4-OHA (4-hydroxyandrostenedione). FCE 24928 caused time-dependent inhibition of human placental aromatase with a t1/2 of 4 min and Ki of 59 nM. Enzyme inactivation by FCE 24928 was faster than by FCE 24304 (t1/2 13.9 min). In PMSG-treated rats, microsomal ovarian aromatase activity was reduced 24 h after FCE 24928 dosing by both the s.c. (ED50 1.2 mg/kg) and the oral (ED50 14.1 mg/kg) routes. The compound was more potent than FCE 24304 and 4-OHA (ED50 1.8 and 3.1 mg/kg s.c.). FCE 24928 did not show any interference with 5 alpha-reductase and desmolase activity nor any significant binding affinity for androgen and estrogen receptors. Slight binding affinity for androgen receptor was observed with FCE 24304 and 4-OHA (0.21 and 0.25% of DHT). In immature, castrated rats, FCE 24928 did not show any intrinsic androgenic activity, up to 100 mg/kg/day s.c., in contrast to a slight androgenic activity observed with FCE 24304 at 10 mg/kg s.c.
Di Salle
E
E
Oncology Line R&D, Farmitalia Carlo Erba, Nerviano, Italy.
Giudici
D
D
Ornati
G
G
Briatico
G
G
D'Alessio
R
R
Villa
V
V
Lombardi
P
P
D000730:Androstadienes / Q000494:pharmacology; D000735:Androstenedione / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D047072:Aromatase Inhibitors; D005260:Female; D008297:Male; D011247:Pregnancy; D051381:Rats; D011919:Rats, Inbred Strains
D000730:Androstadienes; D047072:Aromatase Inhibitors; D000735:Androstenedione; C056516:exemestane; C014594:formestane