INSL3 Variation in Dogs Following Suppression and Recovery of the HPG Axis

Insulin-like peptide 3 (INSL3) is a constitutive product of mature, adult-type Leydig cells of the testes and consequently in most mammals is an ideal biomarker with which to monitor pubertal development. A new heterologous time-resolved fluorescence immunoassay was developed and validated to measure circulating INSL3 in the blood of adult male dogs. Compared to other species, INSL3 concentration is low with marked variation between individuals, which appears to be independent of breed, age, or weight. A model system was then used in which a cohort of beagle dogs was subject to a GnRH-agonist implant to suppress the HPG axis and spermatogenesis, followed by implant removal and recovery. Unlike testosterone, INSL3 levels were not fully suppressed in all animals by the GnRH agonist, nor was the recovery of Leydig cell function following implant removal uniform or complete, even after several weeks. In dogs, and dissimilar from other species (including humans), Leydig-cell INSL3 appears to be quite variable between individual dogs and only weakly connected to the physiology of the HPG axis after its suppression by a GnRH-agonist implant and recovery. Consequently, INSL3 may be less useful in this species for the assessment of testis function

Diagnóstico da artrite reumatoide canina

Canine rheumatoid arthritis is a chronic inflammatory disease that affects the joints of dogs. The inflammation can cause damage to cartilage and bones and early diagnosis is the main factor determining treatment success. This report describes an unusual case of rheumatoid arthritis in a dog, highlighting the relevance of radiographic examination in association with histopathology in the definitive diagnosis. An 8year old, male German Spitz dog, weighing 5kg was admitted with a history of cruciate ligament rupture and grade IV patella dislocation. Previously, surgery had been performed to correct the cranial cruciate ligament rupture, without success. On physical examination, the dog showed a palmigrade stance, severe pelvic limb lameness, and pain on palpation of all joints. Blood count and biochemical analysis were within normal ranges. Orthogonal radiographs of the joints of the pelvic and thoracic limbs were performed. The lesions were bilaterally symmetrical. Samples were taken from the patellofemoral joints for cytology, microbiology, and histopathologic analysis. Rheumatoid factor antibody assay was negative. In conclusion, the combination of more than one clinical sign and diagnostic tests, such as radiographs suggestive of rheumatoid arthritis, histopathologic analysis of the joints, and rheumatoid factor testing is required to reach a definitive diagnosis of rheumatoid arthritis.A artrite reumatóide canina é por definição uma doença crônica inflamatória que acomete as articulações de cães. Como resultado, a artrite reumatoide pode causar lesões na cartilagem e nos ossos e o diagnóstico precoce é o principal fator para o sucesso do tratamento ideal.Este relato de caso objetivou descrever um caso incomum de artrite reumatóide em um cão, destacando a relevância do exame radiográfico associado à histopatologia no diagnóstico definitivo. Foi atendido um cão da raça Spitz Alemão, 8 anos, com 5kg de peso. Anteriormente, foi realizada procedimento cirúrgico para correção da ruptura bilateral de ligamento cruzado e luxação de patela grau IV, porém sem sucesso. Ao exame físico, o cão apresentava posição palmígrada, intensa claudicação dos membros pélvicos e sensibilidade dolorosa de todas as articulações à palpação. As análises de hemograma e bioquímica sérica básica estavam dentro dos limites normais. Foram realizadas radiografias ortogonais das articulações dos membros pélvicos e torácicos. A distribuição das lesões foi simétrica e em ambos os lados. Considerando esses achados, foram obtidas amostras biológicas das articulações para análise citológica, microbiológica e análise histopatológica. O anticorpo fator reumatóide também foi realizado e o resultado foi negativo. Diante do exposto, é necessária a associação de mais de um sinal clínico e diferentes exames, como por exemplo, radiografias sugestivas de artrite reumatóide, análise histopatológica das articulações e anticorpo fator reumatóide para alcançar o diagnóstico definitivo de artrite reumatóide

INSL3 Variation in Dogs Following Suppression and Recovery of the HPG Axis

Insulin-like peptide 3 (INSL3) is a constitutive product of mature, adult-type Leydig cells of the testes and consequently in most mammals is an ideal biomarker with which to monitor pubertal development. A new heterologous time-resolved fluorescence immunoassay was developed and validated to measure circulating INSL3 in the blood of adult male dogs. Compared to other species, INSL3 concentration is low with marked variation between individuals, which appears to be independent of breed, age, or weight. A model system was then used in which a cohort of beagle dogs was subject to a GnRH-agonist implant to suppress the HPG axis and spermatogenesis, followed by implant removal and recovery. Unlike testosterone, INSL3 levels were not fully suppressed in all animals by the GnRH agonist, nor was the recovery of Leydig cell function following implant removal uniform or complete, even after several weeks. In dogs, and dissimilar from other species (including humans), Leydig-cell INSL3 appears to be quite variable between individual dogs and only weakly connected to the physiology of the HPG axis after its suppression by a GnRH-agonist implant and recovery. Consequently, INSL3 may be less useful in this species for the assessment of testis function