Pergamon Chemosphere, Vol. 39, No. 8, pp. 1249-1252, 1999 © 1999 Elsevier Science Ltd. All rights reserved 0045-6535/99/$ - see front matter PII: S0045-6535(99)00192-7 EFFECTS OF ORGANOCHLORINE XENOBIOTICS ON HUMAN SPERMATOZOA L. Silvestroni* and S. Palleschi Department of Medical Physiopathoiogy, University of Rome "La Sapienza" Viale del Policlinico, 00161 Rome, Italy ABSTRACT The organochlorine insecticide lindane is a widely distributed environmental pollutant belonging to the growing family of endocrine disrupting chemicals (EDCs). Lindane intercalates into the sperm membrane and alters the molecular dynamics of the bilayer. In the present paper, preliminary data are reported showing that doses of iindane as low as those found in the female genital tract secretions inhibit the sperm cytological responsiveness to progesterone, the physiological agonist which stimulates the onset of acrosome reactions at the site of fertilization. The hypothesis is put forth that even background levels of lindane may exert antifertility effects independently on the health status of either the male and female reproductive organs. ©1999 ElsevierScienceLtd. All rightsreserved INTRODUCTION Though banned for many years in the industrialized world, the organochlorine insecticide lindane (the ~/- isomer of hexachlorocyclohexane) is still present in the global environment. Lipophylicity and the high chemical stability make lindane accumulate in living organisms and persist in fat tissues and in fat-rich organs for life. A vast literature exists showing that lindane exerts neurotoxic [1], hepatotoxic [2], and uterotoxic [3] effects. As for the reproductive field, environment pollutants endowed with horrnone/antihormone activity (the so-called endocrine disrupting chemicals, EDCs) are presently at the focus of a flaring debate on whether and which relationships exist linking EDCs to the decline of the birth rate and the supposed worsening of human semen quality in the western countries. In fact, the male gonad has been found to be a highly sensitive target organ for lindane. The insecticide accumulates in the testis where it damages the germinal epithelium by producing reduction of the spermatids number and Sertoli cells fragmentation [4], and impairs androgen synthesis in Leydig cells [5]. Much less is known about the effects of lindane on spermatozoa. In a recent paper, we reported that in human spermatozoa the insecticide induces membrane depolarization and influx of extracellular Ca 2÷ through voltage-operated calcium channels. By using laurdan, a fluorescent probe with extreme susceptibility to both the number and kinetics of water dipoles, we demonstrated that lindane interacts with the sperm surface by intercalating among the phospholipids and alters intramembrane dipole dynamics [6]. Consequent to lindane-induced intramembrane dipole reorienting is the dissipation of the membrane intrinsic potential, which in its turn activates low-threshold voltage-operated Ca 2+ channels. The initial Ca 2+ influx produces further depolarization and the opening of additional Ca 2+ channels. In the present communication, some preliminary results are described showing that lindane modifies the sperm 1249