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This Article Full Text Full Text (PDF) All Versions of this Article: 293/5/E1385    most recent 00274.2007v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Pinilla, L. Articles by Aguilar, E. Search for Related Content PubMed PubMed Citation Articles by Pinilla, L. Articles by Aguilar, E.

Selective role of neuropeptide Y receptor subtype Y₂ in the control of gonadotropin secretion in the rat

Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba; and Centro de Investigación Biomédica en Red (CB06/03) Fisiopatología de la Obesidad y Nutrición, Instituto Salud Carlos III, Madrid, Spain

Submitted 2 May 2007 ; accepted in final form 31 August 2007

Different signals with key roles in energy homeostasis regulate the reproductive axis. These include neuropeptide Y and polypeptide YY_3-36, whose type Y₂ receptor is the most abundant of this family in the brain. We evaluated herein the putative roles of Y₂ receptors in the control of gonadotropin secretion by means of central administration of PYY_13-36 (agonist of Y₂ receptors) and BIIE 0246 (antagonist of Y₂ receptors) to intact and orchidectomized male rats. In addition, the ability of PYY_13-36 to elicit GnRH and gonadotropin secretion in vitro and the impact of fasting on LH responses to PYY_13-36 in vivo were also monitored. Central administration of PYY_13-36 significantly decreased the circulating levels of both gonadotropins, an effect that was observed in prepubertal and adult rats. Yet a dual action of Y₂ receptors in the control of male gonadotropic axis was evidenced as their activation induced 1) stimulation of gonadotropin responses to GnRH at the pituitary but 2) inhibition of GnRH secretion at the hypothalamus. Antagonization of Y₂ receptors failed to modify basal LH secretion in intact males either after being fed ad libitum or after being fasted. In contrast, their central blockade in orchidectomized rats evoked a significant increase in circulating LH and FSH level, suggesting the constitutive activation of Y₂ receptor in such stimulated conditions. In summary, our data evidence a complex mode of action of Y₂ receptors in the control of gonadotropic axis, with stimulatory and inhibitory actions at different levels of the system that are sensitive to the gonadal status.

polypeptide YY_3-36; luteinizing hormone-releasing hormone; luteinizing hormone; follicle-stimulating hormone; fasting; pituitary