RESUMO
Normal sexual differentiation depends on completion of chromosomal sex determination, gonadal differentiation, and development of the phenotypic sex. An irregularity in any of these three steps can lead to a disorder in sexual development (DSD). We examined nine dogs with DSD by abdominal ultrasonography, laparotomy, histologic examination of the gonads, and reproductive tract, cytogenetic analysis, and mRNA expression of the SRY gene. We also determined the plasma concentrations of luteinizing hormone (LH), estradiol-17ß, and testosterone before and after administration of gonadotropin-releasing hormone (GnRH) and compared these results with those obtained in anestrous bitches and male control dogs. The gonads of three dogs with DSD contained both testicular and ovarian tissue, while in the other six only testicular tissue was found. Each of the dogs had a uterus. Based on gynecologic examination, cytogenetic analysis, and the histology of the gonads, seven of the nine dogs appeared to be XX sex reversals. Three of these were XX true hermaphrodites and four were XX males; the other two dogs had incomplete XY gonadal dysgenesis. All seven XX sex-reversed dogs were found to be negative for the SRY gene by polymerase chain reaction. The basal plasma luteinizing hormone (LH) concentration was significantly higher in dogs with DSD than in anestrous bitches but not significantly different from that in male dogs. The basal plasma LH concentration increased significantly after GnRH administration in all dogs with DSD. The basal plasma estradiol concentration was significantly higher in dogs with DSD than in anestrous bitches but not significantly different from that in male dogs. The basal plasma testosterone concentration was lower in dogs with DSD than in male dogs. In all dogs with DSD both the basal and GnRH-induced plasma testosterone concentrations were above the upper limit of their respective ranges in the anestrous bitches. In conclusion, the secretion of LH and estradiol in these dogs with DSD, all of which had testicular tissue in their gonads, was similar to that in male control dogs. These results indicate that the basal and/or GnRH-stimulated plasma testosterone concentration might be used to detect the presence of testicular tissue in dogs with DSD.
Assuntos
Transtornos do Desenvolvimento Sexual/veterinária , Doenças do Cão/fisiopatologia , Ovário/fisiopatologia , Hipófise/fisiopatologia , Testículo/fisiopatologia , Animais , Transtornos do Desenvolvimento Sexual/patologia , Transtornos do Desenvolvimento Sexual/fisiopatologia , Cães , Estradiol/sangue , Feminino , Hormônio Foliculoestimulante/sangue , Genes sry/genética , Disgenesia Gonadal/veterinária , Hormônio Liberador de Gonadotropina , Hormônio Luteinizante/sangue , Masculino , Ovário/patologia , Transtornos Ovotesticulares do Desenvolvimento Sexual/veterinária , Progesterona/sangue , RNA Mensageiro/análise , Testículo/patologia , Testosterona/sangueRESUMO
GnRH-stimulation tests were performed in 14 female and 14 male client-owned dogs of several breeds, before and 4 to 5 mo after gonadectomy. The aim of the study was to obtain more insight into the pituitary-gonadal axis in intact and neutered dogs and to establish reference values. Basal plasma luteinizing hormone (LH) and follicle-stimulating hormone (FSH) concentrations were increased significantly after gonadectomy in both bitches and male dogs. In both males and females ranges of the basal plasma FSH concentrations, before and after gonadectomy, did not overlap as opposed to the overlap in ranges of the basal plasma LH concentrations. Before gonadectomy basal plasma LH concentrations were lower and basal plasma FSH concentrations were higher in bitches than in male dogs. After gonadectomy these basal values did not differ significantly. GnRH administration before gonadectomy resulted in an increase in plasma LH and FSH concentrations in both genders. GnRH administration after gonadectomy produced an increase only in plasma LH concentrations in both genders, and a just significant increase in plasma FSH in castrated male dogs. GnRH administration before gonadectomy resulted in a significant increase in plasma testosterone concentration in both genders. In males ranges of basal and GnRH-stimulated plasma testosterone concentrations before and after gonadectomy did not overlap. Basal plasma estradiol concentrations were significantly higher in intact males than in castrated males and their ranges did not overlap. The basal estradiol concentrations in bitches before and after ovariectomy were not significantly different. At 120 min after GnRH administration, ranges of plasma estradiol concentration of intact and ovariectomized bitches no longer overlapped. In conclusion, basal plasma FSH concentration appears to be more reliable than basal plasma LH concentration for verification of neuter status in both male and female dogs. The basal plasma testosterone concentration appears to be reliable for verification of neuter status in male dogs. The plasma estradiol concentration at 120 min after GnRH administration can be used to discriminate between bitches with and without functional ovarian tissue.
Assuntos
Castração , Hormônio Liberador de Gonadotropina/farmacologia , Gônadas/efeitos dos fármacos , Hipófise/efeitos dos fármacos , Animais , Cães , Estradiol/sangue , Feminino , Hormônio Foliculoestimulante/sangue , Gônadas/fisiologia , Hormônio Luteinizante/sangue , Masculino , Orquiectomia/veterinária , Ovariectomia/veterinária , Ovário/efeitos dos fármacos , Ovário/fisiologia , Hipófise/fisiologia , Testículo/efeitos dos fármacos , Testículo/fisiologia , Testosterona/sangueRESUMO
It can be difficult to confirm the presence of remnant ovarian tissue (ROT) in bitches that are presumed to be ovariohysterectomised. A GnRH stimulation test can be used to distinguish ovariectomised bitches from those in anoestrus, but it is uncertain whether the GnRH-induced changes in plasma LH and oestradiol concentrations that occur in intact bitches also occur in ROT-bitches. We report here eighteen ROT-bitches and compare the results of GnRH stimulation tests with those of six ovariectomised and six bitches in anoestrus. The basal (n = 17) and/or GnRH-stimulated (n = 18) plasma oestradiol concentration was above the detection limit of the assay, i.e., < 7 pmol/l, in all ROT-bitches but below the detection limit in all ovariectomised bitches. Basal plasma LH concentration was significantly higher in ROT-bitches (4.1 ± 0.7 µg/L) than those in anoestrus (0.64 ± 0.04 µg/L), and significantly lower than in ovariectomised bitches (20.2 ± 3.6 µg/L). Basal plasma LH concentration was relatively high in bitches in which there was a long interval between ovariectomy and appearance of oestrus. GnRH administration resulted in a significant increase in plasma LH and oestradiol concentrations in ROT-bitches. The GnRH-induced increase and subsequent decline in plasma LH concentration were significantly less in ROT-bitches than in either ovariectomised bitches or those in anoestrus. The GnRH-induced increase in plasma oestradiol concentration was significantly smaller in ROT-bitches than in those in anoestrus. In conclusion, the results of this study demonstrate that in dogs ROT is associated with noticeable changes in the pituitary-ovarian axis and suggest that a GnRH stimulation test may be used to distinguish between completely ovariectomised bitches and those with ROT.
Assuntos
Cães/fisiologia , Ovário/patologia , Hipófise/fisiologia , Animais , Estradiol/sangue , Ciclo Estral/sangue , Feminino , Hormônio Liberador de Gonadotropina/farmacologia , Hormônio Luteinizante/sangue , Ovariectomia/veterinária , Ovário/diagnóstico por imagem , Ovário/cirurgia , Progesterona/sangue , UltrassonografiaRESUMO
Information on the pituitary-ovarian axis in dogs with a granulosa cell tumor (GCT) is lacking. Therefore, we investigated the plasma concentrations of luteinizing hormone (LH) and estradiol before and after gonadotropin-releasing hormone (GnRH) administration in seven bitches with a functional GCT (GCT-total), of which three were intact (GCT-intact) and four had remnant ovarian tissue (GCT-ROT). The results of the GnRH stimulation test were compared with those in six anestrous and six ovariectomized bitches. The most noteworthy results were as follows. The basal plasma LH concentrations of the GCT-ROT bitches were higher (P<0.05) than those of the anestrous bitches. The increment in the plasma LH concentration after GnRH administration in the GCT-total bitches was lower (P<0.001) than the increments in both the anestrous and ovariectomized bitches. The basal plasma estradiol concentrations in the GCT-total bitches were higher (P<0.001) than those in the anestrous and ovariectomized bitches. In conclusion, the pituitary-ovarian axis is affected in bitches with a functional GCT and is characterized by relatively high plasma LH concentrations in GCT-ROT bitches and a subnormal LH response to GnRH stimulation in all GCT bitches compared with those in anestrous and ovariectomized bitches. The relatively high proportion of dogs with remnant ovarian tissue among the GCT bitches suggests a pathogenetic role for elevated gonadotropin secretion in the pathogenesis of GCT.
Assuntos
Doenças do Cão/metabolismo , Tumor de Células da Granulosa/veterinária , Neoplasias Ovarianas/veterinária , Ovário/metabolismo , Hipófise/metabolismo , Animais , Cães , Estradiol/sangue , Feminino , Hormônio Liberador de Gonadotropina/farmacologia , Tumor de Células da Granulosa/diagnóstico por imagem , Tumor de Células da Granulosa/metabolismo , Hormônio Luteinizante/sangue , Neoplasias Ovarianas/diagnóstico por imagem , Neoplasias Ovarianas/metabolismo , Ovariectomia , Ovário/efeitos dos fármacos , Ovário/patologia , Hipófise/efeitos dos fármacos , UltrassonografiaRESUMO
BACKGROUND: Several endocrine disorders that affect humans also occur as endocrinopathies in companion animals. Spontaneous endocrine disorders in animals may provide valuable information for their counterparts in human endocrinology. For example, the discovery of progesterone-induced growth hormone production in the mammary gland of dogs may have important consequences for understanding the pathogenesis of breast cancer in women. In addition, the majority of diabetic cats have a type of diabetes mellitus that closely resembles type 2 diabetes mellitus in humans and therefore may serve as an animal model for this disease in humans. This review describes several endocrine diseases in companion animals that are quite similar to those in humans and emphasizes their usefulness as spontaneous animal models for human endocrine disorders.
Assuntos
Doenças do Sistema Endócrino/veterinária , Animais , Doenças do Gato/diagnóstico , Gatos , Síndrome de Cushing/diagnóstico , Diabetes Mellitus/veterinária , Doenças do Cão/diagnóstico , Cães , Doenças do Sistema Endócrino/diagnóstico , Doenças do Sistema Endócrino/imunologia , Transtornos do Crescimento/diagnóstico , Transtornos do Crescimento/veterinária , Hiperaldosteronismo/diagnóstico , Hiperaldosteronismo/veterinária , Síndrome , Doenças da Glândula Tireoide/diagnósticoRESUMO
Normal mammalian sex differentiation takes place in three genetically controlled steps: chromosomal sex determination (XX or XY), gonadal differentiation and development of the phenotypic sex. Animals are considered to be sex reversed if chromosomal sex determination and gonadal development are not in agreement. In this report, sex reversal is described in a 1.5-year-old Podenco dog that was referred because of suspected recurrent growth of a previously removed os clitoridis in the vulva. With that exception the dog was phenotypically female, but had never been in oestrus and exhibited male behaviour. Abdominal ultrasonography showed a small tubular structure dorsal to the bladder, consistent with a uterus. An ovoid structure resembling a gonad was visible between the right kidney and inguinal canal. Plasma testosterone concentrations before and after GnRH administration indicated the presence of functional testicular tissue. Two testes, each with its epididymis and ductus deferens, and a complete bicornuate uterus were removed surgically. Cytogenetic analysis of peripheral blood lymphocytes showed a normal female karyotype (78, XX). These findings are consistent with the diagnosis of an XX male. PCR analysis of genomic DNA revealed that the SRY gene was absent. In summary, this report describes the first SRY-negative XX male Podenco dog with an almost complete female phenotype despite high basal and stimulated plasma testosterone concentrations. It is hypothesized that the clinical observations in this dog may have been caused by reduced and delayed Müllerian-inhibiting substance secretion and the absence of conversion of testosterone to dihydrotestosterone due to 5alpha-reductase deficiency.
Assuntos
Cães/genética , Diferenciação Sexual , Proteína da Região Y Determinante do Sexo/análise , Animais , DNA/análise , Transtornos do Desenvolvimento Sexual , Estradiol/sangue , Feminino , Genitália Feminina/anatomia & histologia , Genitália Feminina/diagnóstico por imagem , Hormônio Liberador de Gonadotropina/administração & dosagem , Hormônio Luteinizante/sangue , Masculino , Fenótipo , Reação em Cadeia da Polimerase , Processos de Determinação Sexual , Diferenciação Sexual/genética , Proteína da Região Y Determinante do Sexo/genética , Testículo/anatomia & histologia , Testículo/crescimento & desenvolvimento , Testosterona/sangue , UltrassonografiaRESUMO
The basal and gonadotropin releasing hormone (GnRH)-induced plasma concentrations of follicle stimulating hormone (FSH) and luteinizing hormone (LH) were studied in four anestrous and four ovariectomized (OVX) bitches. Blood samples were obtained via jugular venipuncture 40min before and 0, 10, 20, 30, 60, 90, and 120min after the i.v. administration of synthetic GnRH in a dose of 10microg/kg body weight. The basal plasma FSH and LH concentrations were significantly higher in the OVX bitches than in the anestrous bitches. In the anestrous bitches, the plasma FSH concentration was significantly higher than the pretreatment level at 10, 20, and 30min, whereas the plasma LH concentration was significantly elevated at 10 and 20min. The maximal GnRH-induced plasma FSH concentration in the anestrous bitches did not surpass the lowest plasma FSH concentration in the OVX bitches, whereas the GnRH-induced plasma LH concentrations in the anestrous bitches overlapped with the basal plasma LH concentrations in the OVX bitches. In the OVX bitches, GnRH administration did not induce a significant change in the plasma FSH concentration, whereas the plasma LH concentration increased significantly at 10 and 20min. In conclusion, the results of the present study indicate that in anestrous bitches GnRH challenge results in increased plasma levels of both FSH and LH, whereas in the OVX bitches, in which the basal plasma FSH and LH concentrations are higher, only a rise in the plasma LH concentration is present after GnRH stimulation. The results also suggest that a test to measure plasma concentration of FSH in single samples appears to have potential in verification of neuter status in bitches.
Assuntos
Anestro/sangue , Cães/sangue , Hormônio Foliculoestimulante/sangue , Hormônio Liberador de Gonadotropina/farmacologia , Hormônio Luteinizante/sangue , Ovariectomia/veterinária , Animais , Área Sob a Curva , Feminino , Hormônio Foliculoestimulante/metabolismo , Ensaio Imunorradiométrico/veterinária , Hormônio Luteinizante/metabolismo , Radioimunoensaio/veterinária , Reprodutibilidade dos Testes , Estatísticas não ParamétricasRESUMO
The aim of this study was to determine the effects of gonadotrophin releasing hormone (GnRH) administration on the plasma concentrations of reproductive hormones in intact and ovariectomized (OVX) bitches. Therefore, blood samples were collected at multiple times before and after the administration of 10 microg/kg GnRH (Fertagyl)) for the determination of the plasma concentrations of luteinizing hormone (LH), oestradiol, progesterone and testosterone in six anoestrus and in six OVX bitches. The mean plasma LH concentrations before and 60 min after GnRH administration were significantly lower in the anoestrous bitches than in the OVX bitches. In both groups GnRH administration resulted in a significant increase in the plasma LH concentration. The highest plasma LH concentrations were found at 10 min after GnRH administration and these values did not differ significantly between the two groups. Only in the anoestrous bitches a significant increase in plasma oestradiol concentrations was found after GnRH administration and these values were significantly higher than those in the OVX bitches. The plasma concentrations of progesterone and testosterone were low (close to or below the limit of quantitation) both before and after GnRH administration and the differences between anoestrous and OVX bitches were not significant. It can be concluded that (i) basal plasma LH concentration is significantly higher in OVX bitches than in anoestrous bitches, (ii) plasma LH concentration increases after GnRH administration in both anoestrous and OVX bitches, (iii) GnRH administration causes a significant rise in plasma oestradiol concentration only if ovarian tissue is present and (iv) measurement of plasma progesterone and testosterone concentrations before and after GnRH administration does not aid in distinguishing between anoestrous and OVX bitches. The results of this study may provide a basis for the diagnosis of remnant ovarian tissue and verification of neuter status in the bitch.