Behandling av hanhundar med deslorelin

Abstract: This article presents a survey of male dogs treated with the gonadotropin releasing hormone (GnRH) agonist deslorelin (Suprelorin®, Virbac) at three animal clinics in central Sweden. Filled-in questionnaires from 110 dogs were received. The paper also includes a review of existing litterature concerning reproduction in male dogs, focusing on endocrinology, the effects of gonadectomy and the GnRH agonist deslorelin. Continuous treatment with deslorelin produces infertility in male dogs. The pituitary is initially stimulated by deslorelin leading to a rise in luteinizing hormone (LH) and follicle stimulating hormone (FSH) secretion. As a consequence the testosterone levels also increase temporarily. With long term treatment the receptors of the pituitary get desensitized, resulting in decreased production of LH, FSH and testosterone with subsequent suppression of spermatogenesis. The effect remains for at least 6 months. The purpose of this study is to investigate the causes of treatment and if, when and for how long the dog owners notice any effect of the treatment as well as if any adverse effects are seen. It is also considered whether the initial rise in testosterone levels is apparent for the dog owners and if it is possible for them to observe any change in, for example, behavior or worsening of already existing signs from an enlarged prostate. It turned out that the most common indications for treatment is different sexual behaviors, aggression and various prostatic disease, mainly benign prostatic hyperplasia. Most of the dog owners tested treatment with deslorelin instead of gonadectomy because they wanted to evaluate the effect of castration on the dog before letting the dog undergo an irreversible surgical procedure. In most of the dogs the owner noticed the effect of treatment within 4 weeks. In 53 % of the dogs, the owners found that the treatment had had full desired effect and in 16 % there were no desired effect at all. Only occasional dogs showed deterioration of sexual and aggressive behavior during the first month of treatment. None of the dogs treated for prostatic disease showed worsening of prostatic symptoms in the beginning of the treatment, witch indicate that the initial increase in testosterone levels doesn't cause the prostate to grow. Other effects on treated dogs noticed by dog owners were reduced sexual behavior and interest in female dogs, reduced aggression, increased appetite and also that some dogs showed less difficulties to urinate or defecate. Mean duration of a single treatment with Suprelorin® (Virbac) turned out to be 7,8 months with a variation from 3 to 15 months.