1. Introduction
Male reproductive tissues are constantly exposed to
reactive oxygen species (ROS) generated as products of
normal metabolism, and during the fertilization process
spermatozoa normally pass through an area of high
oxygen level [1]. Unlike low ROS levels which stimulate
spermatozoa hyperactivity, capacitation and acro-
* Corresponding author. Tel.: 385 1 239 0321; fax: 385
2441390.
E-mail address: smarko@vef.hr (I.M. Balic´).
Available online at www.sciencedirect.com
Theriogenology 78 (2012) 423–431
www.theriojournal.com
0093-691X/$ – see front matter © 2012 Elsevier Inc. All rights reserved.
doi:10.1016/j.theriogenology.2012.02.022