ABSTRACT
Progesterone (P4) is the only hormone needed to maintain pregnancy in dogs. Therefore, a competitive inhibitor of 3ß-hydroxysteroid dehydrogenase (3ß-HSD) could be a safe and effective option to terminate pregnancy by inhibiting P4 synthesis. To address this hypothesis, we investigated the efficacy of trilostane (TRL), a competitive inhibitor of 3ß-HSD, in terminating pregnancy in dogs. Twenty-one dogs between days 30 and 38 of pregnancy were randomly assigned to one of two treatment groups (trilostane (TRL) and aglepristone (AGL)) and an untreated control (CON) group (n = 7 dogs each). Fetal heart rates (FHRs) (measured at 12 h intervals) and serum P4 concentrations (measured at 6 h intervals) were evaluated. The pregnancy termination rates were 0% and 100% in the TRL and AGL groups, respectively. The decrease in the FHR in the TRL and AGL groups was significantly lower than that observed in the CON group. There was a marked decrease in P4 concentrations in the TRL group 6, 54, and 102 h after the initiation of treatment. The luteal expression of StAR appeared to be weaker in the AGL group than the CON group. In conclusion, although a treatment-induced decrease was observed in plasma P4 concentrations, a seven-day TRL treatment alone was not effective in terminating pregnancies. Further studies are needed on the effects of the prolonged administration of TRL with varying doses and frequencies for the termination of mid-term pregnancy in dogs.
ABSTRACT
The aim of this study was to evaluate the postoperative analgesic and antioxidant effects of butorphanol given in the preoperative or early postoperative period. Twenty-seven healthy female dogs undergoing ovariohysterectomy were randomly divided into three groups as before surgery group (BSG, n = 7) received butorphanol 30 min before preanesthetic administration, after surgery group (ASG, n = 10) received butorphanol during the last skin suture and the control group (CG, n = 10) received no butorphanol. Pain was assessed with short form of the Glasgow composite pain scale (CMPS-SF). Serum concentration of malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase activities (GPx) were quantified by spectrophotometric methods to assess oxidative stress status. The pain score increased rapidly at 1 h after surgery and then decreased gradually towards to 24 h in all groups. There was no statistical difference among the groups in terms of CMPS-SF scores (P > 0.05). Serum concentration of MDA was lower in ASG than in BSG and CG from 1 h to 24 h after surgery. Serum activity of GPx was higher in ASG than in BSG and CG from 2 h to 24 h (P < 0.05). Serum activity of SOD was higher in ASG than in BSG and CG from 1 h to 24 h after surgery (P < 0.05). Serum SOD activity at different time points in ASG did not differ compared to preoperative level though it decreased significantly from 1 h onwards both in CT and BSG. The results indicate that single butorphanol administration either before or after the operation might not provide sufficient analgesia, however, it seems that it has antioxidant potential and may protect tissues by reducing oxidative stress when administered early postoperative period following ovariohysterectomy.
