586EFFECTS OF ALPHA-1 ADRENERGIC RECEPTOR BLOCKADE ON INSULIN-REGULATED AMINOPEPTIDASE (IRAP) ACTIVITY IN THE HYPOTHALAMUS-PITUITARY-GONADS AXIS OF MALE AND FEMALE RATSInsulin-regulated aminopeptidase (IRAP) degrades oxytocin (OTX). OTX is involved in both male and female reproduction, acting at several levels of the hypothalamus-pituitary-gonads (HPG) axis. The neural pathway that drives OTX neurons involves noradrenergic cells in the brainstem, mainly acting through alpha-1-adrenergic receptors. The aim of the present work is to analyze the effects of the administration of the long-lasting alpha-1 adrenergic receptor blocker doxazosin on IRAP activity in the HPG axis of male and female Wistar rats, to determine the existence of gender differences at different levels of the axis and to provide information on the role of IRAP in processing its peptide substrates. Our results suggest that alpha-1 adrenergic receptor blockade with doxazosin acts differently in males and females and affects all the levels of IRAP activity in the HPG axis, indicating also a multimodal regulation of their peptide substrate and therefore, its neuroendocrine functions.marrazol@ujaen.esResearch632015Insulin-regulated aminopeptidase,Adrenergic receptors,Doxazosin,Gender differencesMaría Jesús Ramírez-Expósito, José Manuel Martínez-Martos,Marcela Arrazola-Saniger Experimental and Clinical Physiopathology Research Group BIO296, University of Jaén, Jaén, Spain,Department of Health Sciences,University of Jaén, Jaén, Spain, Faculty of Experimental Sciences, University of Jaén, Jaén, Spain