A high level of male sexual activity is necessary for the activation of the medial preoptic area and the arcuate nucleus during the ‘male effect’ in anestrous goats Marie Bedos a,1 , Wendy Portillo b,1 , Jean-Philippe Dubois c,d,e , Gerardo Duarte a , José A. Flores a , Philippe Chemineau c,d,e , Matthieu Keller c,d,e,1 , Raúl G. Paredes b,1 , José A. Delgadillo a, ⁎ ,1 a Centro de Investigación en Reproduccion Caprina (CIRCA), Universidad Autonoma Agraria Antonio Narro, Torreon, Mexico b Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Querétaro, Mexico c Laboratoire de la Physiologie de la Reproduction & des Comportements, CNRS UMR 7247, Nouzilly, France d INRA, UMR 85, Nouzilly, France e Université François Rabelais, Tours, France HIGHLIGHTS • We studied the activation of mPOA and ARC depending on the level of sexual activity. • In both areas, sexually active males induced a higher activation than inactive ones. • Sexually active males did not specifically activate kisspeptin cells. abstract article info Article history: Received 30 October 2015 Received in revised form 28 June 2016 Accepted 26 July 2016 Available online 27 July 2016 In small ungulates such as sheep or goats, the introduction of a male among a group of anovulatory females dur- ing the anestrus season leads to the reactivation of the gonadotrope axis and ovulation, a phenomenon known as the ‘male effect’. In goats, our previous studies have demonstrated the importance of male sexual activity for an efficient reactivation of the gonadotrope axis assessed through ovulation and blood LH pulsatility. In the present experiment, we assessed whether the level of male sexual activity would also induce differential activation of two brain regions of key importance for the reactivation of GnRH activity, namely the medial preoptic area and the hypothalamic arcuate nucleus. In both structures, we observed a differential activation of Fos in females, depend- ing on the level of buck sexual activity. Indeed, goats unexposed to males showed low levels of expression of Fos while those exposed to sexually inactive bucks showed an intermediate level of Fos expression. Finally, the highest level of Fos expression was found in females exposed to sexually active males. However, and contrary to our initial hypothesis, we were not able to find any specific activation of kisspeptin cells in the arcuate nucleus following the introduction of highly sexually active males. As a whole, these results demonstrate that the level of male sexual activity is a key factor to stimulate brain regions involved in the control of the gonadotrope axis in the context of the male effect in goats. © 2016 Elsevier Inc. All rights reserved. Keywords: Seasonality Reproduction Male/female interaction Ovulation c-Fos Kisspeptin 1. Introduction Female sheep and goat show a seasonal pattern of reproductive ac- tivity. Indeed, females exhibit, during the year, an alternation between periods of ovarian activity during the breeding season, and a period of anestrus [1]. Interestingly, this state of anovulation can be overcome through socio-sexual interactions: when anestrous ewes or goats are exposed to sexually active rams or bucks, a high proportion of the fe- males will ovulate and display estrus, and if they mated will become pregnant. This male-induced ovulation was first reported in sheep over 70 years ago and was termed the ‘ram effect’ [2]. In goats, this phe- nomenon was described later [3]. The peripheral response to the introduction of the male has been quite well described: females show a nearly immediate reactivation of Physiology & Behavior 165 (2016) 173–178 ⁎ Corresponding author at: Centro de Investigacion en Reproduccion Caprina (CIRCA), Universidad Autonoma Antonio Narro, Torreon, Mexico; Periférico Raúl López Sánchez y Carretera a Santa Fe, 27054 Torreón, Coahuila, Mexico. E-mail address: joaldesa@yahoo.com (J.A. Delgadillo). 1 Equal participation of the authors. http://dx.doi.org/10.1016/j.physbeh.2016.07.018 0031-9384/© 2016 Elsevier Inc. All rights reserved. Contents lists available at ScienceDirect Physiology & Behavior journal homepage: www.elsevier.com/locate/phb