Ovulation induction and antifertility effects of an LH-RH analogue (AY 25,205) in cyclic rats.
Pro-oestrous rats, treated with fluphenazine dihydrochloride to block ovulation, were used to compare the ovulation-inducing activity of synthetic LH-RH with one of its analogues, [D-Ala-6, des-Gly-NH2-10]-LH-RH ethylamide (AY-25,205). The lowest dose of LH-RH which produced a significant response was 125 ng compared with 2.9 ng AY-25,205. Statistical analysis of the data showed that AY-25,205 was approximately thirty-six times more potent than LH-RH. Treatment with AY-25,205 also induced partial ovulation in metoestrous rats (80 or 160 ng/rat) and apparently normal ovulation in dioestrous rats (10 to 160 ng/rat). The compound (160 ng) failed to induce further ovulation in oestrous rats which ovulated during the previous night. Advancement of premature ovulation in dioestrous rats with AY-25,205 prevented mating behaviour and pregnancy during the treatment cycle. The antifertility effect of the compound disappeared during the following cycle.
D000818:Animals; D004305:Dose-Response Relationship, Drug; D004971:Estrus; D005260:Female; D005298:Fertility / Q000187:drug effects*; D005476:Fluphenazine / Q000494:pharmacology; D007987:Gonadotropin-Releasing Hormone / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology*; D006728:Hormones / Q000494:pharmacology*; D010060:Ovulation / Q000187:drug effects*; D011247:Pregnancy; D051381:Rats; D012726:Sexual Behavior, Animal / Q000187:drug effects
D006728:Hormones; D007987:Gonadotropin-Releasing Hormone; D005476:Fluphenazine