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Gonadotropin-releasing hormone neuron requirements for puberty, ovulation, and fertility.
Herbison, Allan E; Porteous, Robert; Pape, Jean-Rémi; Mora, Jocelyn M; Hurst, Peter R.
Afiliación
  • Herbison AE; Centre for Neuroendocrinology, Department of Physiology, University of Otago School of Medical Sciences, Dunedin, New Zealand. allan.herbison@stonebow.otago.ac.nz
Endocrinology ; 149(2): 597-604, 2008 Feb.
Article en En | MEDLINE | ID: mdl-18006629
ABSTRACT
The absolute requirement for reproduction implies that the hypothalamo-pituitary-gonadal axis, controlling fertility, is an evolutionary robust mechanism. The GnRH neurons of the hypothalamus represent the key cell type within the body dictating fertility. However, the level of functional redundancy within the GnRH neuron population is unknown. As a result of a fortuitous transgene insertion event, GNR23 mice exhibit a marked allele-dependent reduction in GnRH neuron number within their brain. Wild-type mice have approximately 600 GnRH neurons, compared with approximately 200 (34%) and approximately 70 (12%) in GNR23(+/-) and GNR23(-/-) mice, respectively. Using these mice, we examined the minimal GnRH neuron requirements for fertility. Male GNR23(-/-) mice exhibited normal fertility. In contrast, female GNR23(-/-) mice were markedly subfertile, failing to produce normal litters, have estrous cycles, or ovulate. The failure of ovulation resulted from an inability of the few existing GnRH neurons to generate the LH surge. This was not the case, however, for the first cycle at puberty that appeared normal. Together, these observations demonstrate that 12% of the GnRH neuron population is sufficient for pulsatile gonadotropin secretion and puberty onset, whereas between 12 and 34% are required for cyclical control in adult female mice. This indicates that substantial redundancy exists within the GnRH neuronal population and suggests that the great majority of GnRH neurons must be dysfunctional before fertility is affected.
Asunto(s)

Texto completo: 1 Colección: 01-internacional Banco de datos: MEDLINE Asunto principal: Ovulación / Maduración Sexual / Hormona Liberadora de Gonadotropina / Fertilidad / Infertilidad Femenina Límite: Animals Idioma: En Revista: Endocrinology Año: 2008 Tipo del documento: Article País de afiliación: Nueva Zelanda

Texto completo: 1 Colección: 01-internacional Banco de datos: MEDLINE Asunto principal: Ovulación / Maduración Sexual / Hormona Liberadora de Gonadotropina / Fertilidad / Infertilidad Femenina Límite: Animals Idioma: En Revista: Endocrinology Año: 2008 Tipo del documento: Article País de afiliación: Nueva Zelanda