title: Permanent contraception of dogs induced with intratesticular injection of a Zinc Gluconate-based solution.
abstract: The objective was to evaluate the efficacy of a single intratesticular injection of a Zinc Gluconate-based solution to induce sterility in male dogs. Fifteen pubertal mongrel dogs (8 mo to 4 y old) were assigned to two groups; Control dogs (n = 5) received a single injection of an isotonic saline solution into each testis, whereas Treated dogs (n = 10), were given Testoblock, a proprietary zinc-gluconate (13.1 mg zinc/ml) solution in a physiological vehicle. The volume of saline or Testoblock injected varied from 0.2 to 1.0 ml/testis (based on testis width). Physical examination, testis width, hematology, clinical chemistry (hepatic and renal function), plasma testosterone concentration, semen characteristics, and libido, were assessed until castration (150 d after treatment). In Treated dogs, testis width increased (approximately 20%) relative to that in Control dogs, but subsequently was not significantly different from Controls (group × time interaction, P < 0.0001). For all dogs, values for hematology and clinical chemistry consistently remained within reference ranges. Although plasma testosterone concentrations decreased over time (P < 0.006), there was only a tendency for an effect of group (P < 0.09), and libido was not significantly affected. By 63 d after Testoblock treatment, eight Treated dogs were azoospermic, whereas the remaining two were oligozoospermic (<10 × 10(6) sperm/ml). We concluded that intratesticular injection of the Zinc Gluconate-based chemical sterilant Testoblock has considerable potential to induce permanent contraception in male dogs.
authors.affiliation: Department of Veterinary Medicine, UFRPE, Rua Dom Manoel de Medeiros s/n, Dois Irmãos, CEP 52,171 to 52171-900, Recife, PE, Brazil. ecso21@uol.com.br
authors.forename: Erika C S
authors.initials: EC
authors.lastname: Oliveira
authors.forename: Maria Raquel P
authors.initials: MR
authors.lastname: Moura
authors.forename: Marcelo J C
authors.initials: MJ
authors.lastname: de Sá
authors.forename: Valdemiro A
authors.initials: VA
authors.lastname: Silva
authors.forename: John P
authors.initials: JP
authors.lastname: Kastelic
authors.forename: Robert H
authors.initials: RH
authors.lastname: Douglas
authors.forename: Antônio P
authors.initials: AP
authors.lastname: Marques
mesh_terms: D000818:Animals; D003272:Contraceptive Agents, Male / Q000008:administration & dosage / Q000627:therapeutic use*; D005942:Gluconates / Q000008:administration & dosage / Q000627:therapeutic use*; D007267:Injections / Q000662:veterinary; D007989:Libido / Q000187:drug effects; D008297:Male; D013091:Spermatogenesis / Q000187:drug effects; D013245:Sterilization, Reproductive / Q000379:methods / Q000662:veterinary*; D013737:Testis / Q000033:anatomy & histology / Q000187:drug effects*; D013739:Testosterone / Q000097:blood
chemical_list: D003272:Contraceptive Agents, Male; D005942:Gluconates; D013739:Testosterone; C030691:gluconic acid