Interceptive action of azastene and its effects on plasma progesterone in pregnant rats and rabbits

Azastene suspended in tea seed oil (Aza, ig) and 15-methylprostaglandin F2α (15-Me-PGF2α, im), alone or combined, were given to rats on d 10 of pregnancy. A complete interceptive action on pregnancy was obtained after Aza 24 mg/kg alone or 6 mg/kg combined with 15-Me-PGF2α 0.l mg/kg. Plasma progesterone levels were lowered by Aza 24 mg/kg given on d 10 of pregnancy to 114±39 nmol/L (d 14, p<0.01) and 67±23 nmol/L (d 16, p<0.01) in pregnant rats； and by Aza l00 mg/kg given on d 15 and d 16 to 24±8 nmol/L (d 18，p<0.05) and 22±5 nmol/L (d 19, p<0.05) in pregnant rabbits, respectively. Aza (ig) and indomethacin (Ind, ig), alone or combined, were administered to rats on d l0 of pregnancy. The effects of Aza 12 mg/kg on pregnancy were nullified by Ind 4 mg/kg (p<0.05) and 8 mg/kg (p<0.01).