RESUMEN
Insulin like growth factor-1 (IGF-1) plays an important role in the regulation of ovarian function. Despite its extensive study in several species, there is a paucity of information about IGF-1`s function and localization in the canine ovary. The aim of the present study was to assess the effect of IGF-1 on oocyte nuclear maturation and to immunolocalize the IGF-1 and its receptor (IGF-1R) in the ovary. Cumulus-oocyte complexes (COCs) were obtained from 34 bitches. The COCs from each bitch were incubated in TCM 199-HEPES in the absence (n = 199) or presence (n = 204) of 100 ng/ml IGF-1 for 96 hr at 38ºC in 5% CO2 , stained and evaluated for nuclear maturation by fluorescence microscopy. The results showed that the addition of IGF-1 did not have an effect (p Ë 0.05) on the nuclear maturation under these conditions. The immunohistochemical study revealed nuclear and cytoplasmic staining for IGF-1 and IGF-1R, respectively. Both were localized in all ovarian structures including the corpus luteum, but not in the granulosa cells from primordial follicles. In addition, IGF-1 was not localized in the oocytes in tertiary follicles. The results obtained show the presence of IGF-1 through the stages of follicular growth and in the corpus luteum of the canine ovary. However, its role on oocyte nuclear maturation could not be demonstrated.
Asunto(s)
Factor I del Crecimiento Similar a la Insulina/genética , Ovario/metabolismo , Receptor IGF Tipo 1/genética , Animales , Perros , Femenino , Factor I del Crecimiento Similar a la Insulina/metabolismo , Receptor IGF Tipo 1/metabolismoRESUMEN
This report describes a disorder of the sexual development in a beagle dog resulting in an intersex condition. A 6 mo old beagle was presented for evaluation of a protruding structure from the vulva consistent with an enlarged clitoris. Ultrasonographic examination revealed the presence of both gonadal and uterine structures. Retrograde cystourethrovaginogram showed the presence of an os clitoris and severe vaginal stenosis. Histological studies revealed the presence of bilateral ovotestes and uterus. The gonad had interstitial cells within seminiferous-like tubules lined only with Sertoli cells and abundant interstitial cells among primordial, primary, and secondary follicles. Hormone assays completed before and after gonadohysterectomy showed an elevation in the levels of progesterone and dihydrotestosterone that returned to baseline 3 mo after surgery. Testosterone levels that were within the male reference ranges before surgery decreased to basal levels postsurgically. 17-ß-Estradiol levels showed little variation and values were always within the reference ranges for a male. Cytogenetic analysis showed a normal female karyotype (2n = 78, XX) and polymerase chain reaction analysis revealed the absence of the sex-determining region Y gene. In summary, the dog presented bilateral ovotestes and a 2n = 78, XX chromosomal complement lacking the sex determining region Y gene, consistent with a diagnosis of true hermaphroditism.