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Comment |
Novel Expression of Gonadotropin Subunit Genes in Oocytes of the Gilthead Seabream (Sparus aurata)Wong TT, et al 2004 .
It is widely believed that follicle-stimulating hormone (FSH) and LH (LH), which are known to play key roles in controlling the production of functional oocytes in vertebrates, are synthesized and secreted exclusively by the anterior pituitary. Here, we present evidence for the novel expression of FSHbeta, LHbeta and the common glycoprotein-alpha (Cgalpha) in the gilthead seabream ovary. Using in situ hybridization and immunocytochemistry, FSHbeta was detected in primary-growth and secondary-growth-I oocytes, LHbeta was found in secondary-growth oocytes, and Cgalpha was observed in both primary and secondary-growth oocytes. Northern blot analyses demonstrated that Fshbeta transcript is 0.6 kb in both pituitary and ovary, while the ovarian Lhbeta transcript (1.1 kb), unexpectedly, is longer than the known pituitary Lhbeta transcript (0.6 kb). Sequence analyses revealed that ovarian Lhbeta is driven by a different promoter than pituitary Lhbeta, which generates an additional 459 bases at the distal portion of the 5'-untranslated region of the ovarian Lhbeta. Furthermore, using in vitro ovarian fragment incubation, we demonstrated that GnRH agonist, mGnRH-A, enhanced the expression of ovarian Fshbeta (up to 2.7 fold), Lhbeta (up to 1.4 fold), Cgalpha (up to 1.8 fold) and the secretion of ovarian LH (up to 2.2 fold). In contrast, GnRH antagonist, analog E, suppressed the secretion of ovarian LH. Our findings suggest that a GnRH-gonadotropin axis is present in the gilthead seabream ovary and that FSH and LH, the well-characterized pituitary hormones, may have prominent novel roles in teleost intra-ovarian communication between oocytes and ovarian follicle cells.
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Mutations |
2 mutations
Species: mouse
Mutation name: None
type: null mutation
fertility: infertile - non-ovarian defect
Comment: Targeted disruption of luteinizing hormone {beta}-subunit leads to hypogonadism, defects in gonadal steroidogenesis, and infertility Proc Natl Acad Sci U S A. 2004 .
Species: human
Mutation name: None
type: naturally occurring
fertility: subfertile
Comment: Trp28Arg/Ile35Thr LHB gene variants are associated with elevated testosterone levels in women with polycystic ovary syndrome. Batista MC 2014 et al.
INTRODUCTION
Polycystic Ovary Syndrome (PCOS) is a complex endocrine disorder, of multifactorial etiology, which affects 6-10% of women of reproductive age. It is considered the leading cause of anovulatory infertility, menstrual disorders and hyperandrogenism in this population. The genetic basis of PCOS is still largely unknown despite significant family clustering; determining its mode of inheritance is particularly difficult given the heterogenic presentation of the disease.
MATERIALS AND METHODS
130 Brazilian women, aged 14-42years, who met the 2003 Rotterdam criteria for PCOS diagnosis, were included, and 96 healthy women constituted the control group. Presence of hirsutism was classified using the modified Ferriman-Gallwey score (F-G score) as absent (=7), mild (8-14), and severe (=15). Blood levels of luteinizing hormone (LH), total testosterone (TT), dehydroepiandrosterone sulfate (DHEA-S) and androstenedione were determined. The coding region of the luteinizing hormone beta-subunit (LHB) gene was amplified and sequenced. Differences in allelic and genotypic frequency distribution of each polymorphism across controls and cases were estimated by the Mantel-Haenszel chi-square or Fisher's exact test (p<0.05), and the probability of an association between the detection of a polymorphism and presence of a diagnosis of PCOS, by logistic regression.
RESULT(S)
Sequencing detected 8 polymorphisms in the LHB gene coding region. Two polymorphisms in linkage disequilibrium were significantly more prevalent in the presence of hyperandrogenemia: rs1800447/rs34349826 (Trp28Arg/Ile35Thr) (p=0.02).
CONCLUSION(S)
In this series, a modulatory effect of LHB polymorphisms on hyperandrogenemia phenotype of PCOS was observed; however, this finding needs to be replicated in other populations.
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