title: Reversibility of germinative and endocrine testicular function after long-term contraception with a GnRH-agonist implant in the tom-a follow-up study.
abstract: A significantly reduced gonadotropin and testosterone secretion is a well-described result of long-term administration of GnRH agonists in the male dog and cat. To date, no data are available about the duration of efficacy and the reversibility of treatment-induced effects after long-term treatment with a 4.7 mg deslorelin implant. Seven healthy male European Shorthair cats (3.2 ± 0.5 kg, 1-6 years) were treated with a 4.7 mg deslorelin implant. Blood samples (testosterone, T), testicular volume, penile spines, and mating behavior were recorded once weekly. Considering T > 0.5 ng/mL as the biological endpoint, mean duration of efficacy was 78.8 ± 12.9 weeks (range: 61.7-100.7 weeks) with T concentrations increasing rapidly after the last T less than 0.1 ng/mL (basal) (P < 0.0001), and pretreatment T concentrations being reached after 3 weeks. Testicular volume rapidly increased after the first increase of T (P < 0.001) with pretreatment testicular volume being reached after 6.9 ± 3.4 weeks (5-11 weeks). "Normal" libido reoccurred 88.7 ± 12.4 weeks after treatment, and "normal" mating behavior was observed even later. Fertile matings occurred 7 to 42 weeks after the last T less than 0.1 ng/mL with a mean of 4.0 ± 0.0 kittens, and 13.6 to 47.6 weeks afterwards testicular histology revealed normal spermatogenesis. The present data confirm that the use of slow-release GnRH-agonist implants containing deslorelin in tomcats represents an effective and safe reversible alternative for long-term contraception; however, as number of animals is low, further fertility trials are recommended.
authors.affiliation: Klinikum Veterinärmedizin, Klinik für Geburtshilfe, Gynäkologie und Andrologie der Groβ- und Kleintiere, Justus-Liebig Universität Giessen, Giessen, Germany. Electronic address: sgp@sund.ku.dk.
authors.forename: Sandra
authors.initials: S
authors.lastname: Goericke-Pesch
authors.affiliation: Clinic for Obstetrics, Reproduction and Reproductive Disorders of Veterinary Faculty of the Trakian University, Stara Zagora, Bulgaria.
authors.forename: Plamen
authors.initials: P
authors.lastname: Georgiev
authors.affiliation: Clinic for Obstetrics, Reproduction and Reproductive Disorders of Veterinary Faculty of the Trakian University, Stara Zagora, Bulgaria.
authors.forename: Anton
authors.initials: A
authors.lastname: Antonov
authors.affiliation: Institute for Anatomy and Histology of Veterinary Faculty of the Trakian University, Stara Zagora, Bulgaria.
authors.forename: Angel
authors.initials: A
authors.lastname: Vodenicharov
authors.affiliation: Virbac, Medical Department, Carros Cedex, France.
authors.forename: Christelle
authors.initials: C
authors.lastname: Navarro
authors.affiliation: Klinikum Veterinärmedizin, Klinik für Geburtshilfe, Gynäkologie und Andrologie der Groβ- und Kleintiere, Justus-Liebig Universität Giessen, Giessen, Germany.
authors.forename: Axel
authors.initials: A
authors.lastname: Wehrend
mesh_terms: D000818:Animals; D002415:Cats / Q000502:physiology*; D003272:Contraceptive Agents, Male / Q000008:administration & dosage / Q000494:pharmacology*; D004343:Drug Implants / Q000008:administration & dosage*; D005298:Fertility; D007987:Gonadotropin-Releasing Hormone / Q000819:agonists*; D008297:Male; D010413:Penis / Q000033:anatomy & histology / Q000187:drug effects; D012726:Sexual Behavior, Animal; D013737:Testis / Q000187:drug effects* / Q000502:physiology; D017329:Triptorelin Pamoate / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D003272:Contraceptive Agents, Male; D004343:Drug Implants; D017329:Triptorelin Pamoate; D007987:Gonadotropin-Releasing Hormone; C066438:deslorelin
keywords: Deslorelin; Downregulation; Long-term contraception; Male cat; Reversibility