Recrudescence of Spermatogenesis in the Dog Following Downregulation Using a Slow Release GnRH Agonist Implant

Autor: M Schulz, G.R. Özalp, Sandra Goericke-Pesch, A. Spang, Bernd Hoffmann, C. Ludwig, Martin Bergmann
Přispěvatelé: Uludağ Üniversitesi/Veteriner Fakültesi/Kadın Hastalıkları ve Doğum Anabilim Dalı., Özalp, Gözde Rabia, AAE-3607-2019
Rok vydání: 2009
Předmět:
Veterinary sciences
Male
Gonadorelin
Agriculture
dairy & animal science
Gonadotropin-Releasing Hormone
Plasma
Nafarelin
Basal (phylogenetics)
Follicle-stimulating hormone
chemistry.chemical_compound
Endocrinology
Controlled clinical trial
Testis
Dog
Testosterone
Sexual Maturation
Semen quality
Drug Implants
Conference paper
Sperm Count
Agriculture
Sertoli cell
Clinical trial
medicine.anatomical_structure
Randomized controlled trial
Testicular function
Luteinizing hormone
Biotechnology
endocrine system
medicine.medical_specialty
Photoperiod
Drug derivative
Drug potentiation
Reproductive biology
Cycle
Antispermatogenic Agents
Biology
Drug Administration Schedule
Spermatozoon count
Azaglycylnafarelin
Dogs
Drug implant
Internal medicine
medicine
Animals
Spermatogenesis
Animal
Delayed release formulation
Drug administration
Animal disease
Seasonality
Canis familiaris
Antispermatogenic agent
Hormone
Drug effect
Castration
chemistry
Delayed-Action Preparations
Pyometra
Bitches
Deslorelin
Animal Science and Zoology
Cytology
Controlled study
Zdroj: Reproduction in Domestic Animals. 44:302-308
ISSN: 1439-0531
0936-6768
DOI: 10.1111/j.1439-0531.2009.01378.x
Popis: Bu çalışma, 9-11 Temmuz 2008 tarihlerinde Viyana Üniversitesi[Avusturya]'da düzenlenen 6. International Symposium on Canine and Feline Reproduction'da bildiri olarak sunulmuştru. The present study examined the degree to which downregulation with a GnRH agonist impaired spermatogenesis and the time course of morphological and hormonal changes that occurred during recrudescence of spermatogenesis. Using a control group (group 1, n = 5) of dogs, the effect of a removable slow release GnRH-agonist implant was investigated in beagle dogs (group 2, n = 30). The implant was removed after 5 months (week 0) and three to four dogs were castrated at weeks 0, 3, 6, 9, 12, 15, 18, 21 and 24. The degree of downregulation and recrudescence of spermatogenesis was assessed by evaluation of 200 tubular cross-sections, resulting in an assigning of dogs of group 2 to testis developmental groups (DG) according to the most developed germ cell observed: DG A, spermatocytes; DG B, round spermatids; DG C, elongating spermatids and DG D, elongated spermatids. Downregulation led to an arrest of spermatogenesis at the level of spermatogonia/primary spermatocytes. The time course of recrudescence showed high individual variations and the number of dogs falling into DG A, B, C and D was 4, 3, 6 and 17 respectively. Spermatogenesis in group 2, DG D was not different from group 1 (control). In DG A, mean area of Leydig-cell nuclei was lower (p < 0.001) than in the other DG and group 1 and resembled that of juvenile dogs (group 3, n = 3); nuclei of Sertoli cells had changed from more flat/polygonal (group 1, group 2, DG C and D) to round/ovoid and had moved to a more luminal position. As indicated by basal testosterone (T), luteinizing hormone (LH) and follicle stimulating hormone (FSH) concentrations at implant removal, full downregulation had been obtained. Testosterone, LH and FSH concentrations [(g) (DF), ng/ml] increased (p < 0.05) from implant removal to DG B [T: 0.1 (1.24) vs 2.12 (2.31); LH: 0.2 (2.15) vs 1.11 (1.7); FSH: 0.37 (3.50) vs 6.37 (1.68)] and were more or less constant thereafter indicating that onset of spermatogenesis was related to an increase of plasma T occurring in a very narrow time window. Following GnRH implantation, the size of the testes and the prostate decreased by approximately 55% (p < 0.001), they increased to sizes similar to pre-treatment values following implant removal.
Databáze: OpenAIRE
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