Iron-binding metalloproteins in seminal plasma and their possible function as regulatory molecules of sperm metabolism

Abstract

Introduction. Seminal plasma (SP) is a sperm function modulator. Thus, it is necessary to adequately characterize its molecular composition. Iron (Fe) plays an important role in spermatogenesis. The transport, cellular uptake, and storage of Fe involve transferrin (Tf), the cellular membrane receptor for Tf, and ferritin (FN), respectively. The metabolic pathways of Fe in human testes are still unknown. Objectives. The aim of the work was to study biochemical components such as total proteins (TP), Fe, FN and Tf in SP of young individuals, and to establish reference values for our laboratory. These values were then correlated to semen parameters, sperm functional tests and production of reactive oxygen species (ROS) to understand the physiology of Fe in the testis. Materials and Methods. One hundred and fifteen semen and serum samples were studied, and the concentration of Tf, Fe, TP and FN was determined in both fluids. A basic semen analysis and ROS measurement (T-Bars, MOST, Nitrites) were performed. Results and conclusions. The biochemical markers studied were significantly different in seminal plasma and serum, and no relationship was found between them. Tf concentration in SP had a direct linear relationship with sperm concentration and motility. An inverse relationship between oxidative stress and testicular Tf levels was evidenced, which could be due to its antioxidant function in SP. Knowledge of the pathophysiological mechanisms of sperm function is critical for the correct diagnosis and treatment of human infertility.