Data/hora: 21/06/2024 15:40:12

Biblioteca(s): | Embrapa Gado de Leite.
Data corrente: | 13/02/2017
Data da última atualização: | 30/01/2023
Autoria: | CARDOSO, R. C.; ALVES, B. R. C.; SHARPTON, S. M.; WILLIAMS, G. L.; AMSTALDEN, M.
Afiliação: | R. C. CARDOSO, Texas A&M University, College Station, TX, USA; BRUNA RIOS COELHO ALVES, CNPGL; S. M. SHARPTON, Texas A&M University, College Station, TX, USA; G. L. WILLIAMS, Texas A&M University, College Station, TX, USA; M. AMSTALDEN, Texas A&M University, College Station, TX, USA.
Título: | Nutritional Programming of Accelerated Puberty in Heifers: Involvement of Pro-Opiomelanocortin Neurones in the Arcuate Nucleus.
Ano de publicação: | 2015
Fonte/Imprenta: | Journal of Neuroendocrinology, n. 27, p. 647-657, 2015.
Idioma: | Inglês
Conteúdo: | The timing of puberty and subsequent fertility in female mammals are dependent on the inte-gration of metabolic signals by the hypothalamus. Pro-opiomelanocortin (POMC) neurones inthe arcuate nucleus (ARC) comprise a critical metabolic-sensing pathway controlling the reproductive neuroendocrine axis. a-Melanocyte-stimulating hormone (aMSH), a product of thePOMC gene, has excitatory effects on gonadotrophin-releasing hormone (GnRH) neurones andfibres containing aMSH project to GnRH and kisspeptin neurones. Because kisspeptin is a potentstimulator of GnRH release, aMSH may also stimulate GnRH secretion indirectly via kisspeptinneurones. In the present work, we report studies conducted in young female cattle (heifers) aiming to determine whether increased nutrient intake during the juvenile period (4-8 months ofage), a strategy previously shown to advance puberty, alters POMC and KISS1 mRNA expression, as well as aMSH close contacts on GnRH and kisspeptin neurones. In Experiment 1, POMCmRNA expression, detected by in situ hybridisation, was greater (P < 0.05) in the ARC in heifersthat gained 1 kg/day of body weight (high-gain, HG; n = 6) compared to heifers that gained0.5 kg/day (low-gain, LG; n = 5). The number of KISS1-expressing cells in the middle ARC was reduced (P < 0.05) in HG compared to LG heifers. In Experiment 2, double-immunofluorescence showed limited aMSH-positive close contacts on GnRH neurones, and the magnitude of these inputs was not influenced by nutritional status. Conversely, a large number of kisspeptin-immu-noreactive cells in the ARC were observed in close proximity to aMSH-containing varicosities. Furthermore, HG heifers (n = 5) exhibited a greater (P < 0.05) percentage of kisspeptin neuronesin direct apposition to aMSH fibres and an increased (P < 0.05) number of aMSH close contactsper kisspeptin cell compared to LG heifers (n = 6). These results indicate that the POMC-kisspeptin pathway may be important in mediating the nutritional acceleration of puberty inheifers.
Palavras-Chave: | Arcuate nucleus; Kisspeptin.
Thesaurus Nal: | heifers; pro-opiomelanocortin; puberty.
Categoria do assunto: | L Ciência Animal e Produtos de Origem Animal
Registro original: | Embrapa Gado de Leite (CNPGL)
Exemplares: | CNPGL - (23270-1) - UPC - AP - DD -  -  -  - DIS