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The effect of leptin on luteinizing hormone release is exerted in the zona incerta and mediated by melanin-concentrating hormone.
Murray, J F; Mercer, J G; Adan, R A; Datta, J J; Aldairy, C; Moar, K M; Baker, B I; Stock, M J; Wilson, C A.
Afiliación
  • Murray JF; Department of Obstetrics, St George's Hospital Medical School, London, UK.
J Neuroendocrinol ; 12(11): 1133-9, 2000 Nov.
Article en En | MEDLINE | ID: mdl-11069129
The adipose hormone, leptin, not only restrains appetite, but also influences energy expenditure. One such influence is to promote sexual maturation and fertility. The neuromodulatory circuits that mediate this effect are not well known but the present study suggests that one mediator could be melanin-concentrating hormone (MCH). We show that the long-form receptor (Ob-Rb) is expressed in the zona incerta of the rat and that administration of leptin (both 0.5 microg and 1.0 microg/side) into this area of ovariectomized, oestrogen-primed rats stimulated the release of luteinizing hormone (LH) within 1 h, the effect enduring for a further 1 h. Injections of leptin into the arcuate nucleus induced a smaller, transient rise in LH while injections into the paraventricular and ventromedial nuclei were without effect. MCH neurones are present in the zona incerta and administration of this hormone into the medial preoptic area (mPOA) stimulates LH release, therefore we investigated the possibility that MCH might mediate this effect of leptin. An injection of MCH antiserum into mPOA prevented the rise in LH normally induced by leptin injected into the zona incerta. In addition, melanocortin receptor antagonists ([D-Arg8]ACTH(4-10) and [Ala6]ACTH(4-10)), previously shown to inhibit the stimulatory effect of MCH on LH release, also inhibited the effect of leptin. We propose that one route by which leptin may promote reproductive activity is by enhancing MCH release from fibres within the mPOA. Speculative mechanisms for the action of MCH include the following possibilities: MCH may be acting on the specific MCH receptor which in turn interacts with a melanocortin or melanocortin-like receptor; MCH may bind directly to one of the melanocortin receptors; or melanocortin antagonists may interact with the MCH receptor.
Asunto(s)
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Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Hormonas Hipofisarias / Hormona Luteinizante / Receptores de Superficie Celular / Subtálamo / Leptina / Hormonas Hipotalámicas / Melaninas Límite: Animals Idioma: En Revista: J Neuroendocrinol Asunto de la revista: ENDOCRINOLOGIA / NEUROLOGIA Año: 2000 Tipo del documento: Article Pais de publicación: Estados Unidos
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Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Hormonas Hipofisarias / Hormona Luteinizante / Receptores de Superficie Celular / Subtálamo / Leptina / Hormonas Hipotalámicas / Melaninas Límite: Animals Idioma: En Revista: J Neuroendocrinol Asunto de la revista: ENDOCRINOLOGIA / NEUROLOGIA Año: 2000 Tipo del documento: Article Pais de publicación: Estados Unidos