The GnRH antagonist acyline prevented ovulation, but did not affect ovarian follicular development or gestational corpora lutea in the domestic cat

A RISSO; C VALIENTE; Y CORRADA; G. GARCÍA ROMERO; P.G. BLANCO; P.E. DE LA SOTA ; J.D. DIAZ; C GOBELLO

THERIOGENOLOGY

ELSEVIER SCIENCE INC

Año: 2010 vol. 73 p. 984 - 987

0093-691X

Two experiments were conducted to investigate the effects of the GnRH antagonist acyline  (330mg/kg, given sc) on ovarian follicular development and ovulation, as well as on pregnancy maintenance in domestic cats. In the first experiment, seven queens in proestrus (total of 24 proestrus periods), were randomly assigned to treatment with either acyline (ACY; n = 17) or a placebo (PLC; n = 7). All queens were mated with a fertile tomcat. In the ACY and PLC groups, cessation of estrus occurred (mean  SEM) 7.0  1.3 and 7.0  1.7 d after treatment (P > 0.1), ovulation occurred in 2 of 17 and all seven estrus periods (P < 0.05), and pregnancy rates were 1 of 16 and 7 of 7 (P < 0.05), respectively. In the ACYand PLC groups, intervals from treatment to the onset of the ensuing proestrus were 18.4  1.7 and 120  17.2 d. In the second experiment, 14 pregnant queens were randomly allocated, according to theirmating date, to treatment with acyline in early pregnancy (from20 to 25 d, n = 3),mid pregnancy (from26 to 45 d; n = 4), late pregnancy (> 45 d; n = 3), or injection of a placebo in early (n = 1), mid (n = 2), or late pregnancy (n = 1). Ultrasonographic assessments of the uterus were done every second day for 2 wk post treatment, and serum progesterone (P4) concentrations were determined before treatment, and at 7 and 14 d after treatment. No pregnancies were prematurely terminated and post-treatment P4 concentrations did not differ among treatment groups (P > 0.1). In conclusion, in the domestic cat, GnRH withdrawal by acyline prevented ovulation when given in early follicular phase (proestrus), but did not significantly affect luteal function during pregnancy.