Comparison of two doses of the GnRH antagonist, acyline, for pregnancy termination in bitches

VALIENTE C; CORRADA Y; DE LA SOTA PE; BLANCO PG; ARIAS D; GOBELLO C

REPRODUCTION IN DOMESTIC ANIMALS (1990)

Blackwell

Año: 2009 vol. 44 p. 156 - 159

0936-6768

Gonadotropin-releasing hormone (GnRH) antagonists are particularly useful when a rapid inhibitory effect on the gonadal axis is required. The aim of this study was to test the efficacy and clinical safety of a low and high dose of the third generation GnRH antagonist, acyline, on pregnancy termination in female dogs. The effect of the antagonist on the progesterone (P4) serum concentration was also described. Twenty-one mid-pregnant bitches were randomly assigned to a single subcutaneous (SC) dose of a placebo (PLACE; n = 7), a low (ACY-L; 110 lg ⁄ kg; n = 6) or high (ACY-H; 330 lg ⁄ kg; n = 8) dose of acyline. The animals were followed up for 15 days. All ACY treated but no placebo-treated animals terminated their pregnancy by abortion (p < 0.01). The ACY-L and ACY-H groups interrupted their pregnancy 7 ± 1.9 and 6.4 ± 1.3 days after treatment, respectively (p = 0.7). A significant interaction between treatment and day was found (p < 0.01) for P4 serum concentrations when PLACE was compared with both ACY groups. No difference was found for this hormone between both ACY groups (p > 0.05) where P4 diminished throughout the study. The decreasing rate varied among animals and was closely related to the time of abortion when P4 reached basal concentrations. In PLACE animals, gestation progressed normally and P4 did not change throughout the study (p > 0.05). None of the bitches presented side effects. It was concluded that acyline safely terminated mid-pregnancy by permanently decreasing P4 serum concentrations.