Cadmium-induced decrement of the LH receptor expression and cAMP levels in the testis of rats

Cadmium (Cd) is a widespread environmental pollutant, characterized by its ability to affect various organs. Adverse effect of Cd on the testis including decreased testosterone production are well-known phenomena, but the cellular events explaining these effects have not yet been established. In the present study the initial steps of gonadotropin mediated testosterone biosynthesis were examined in vivo in rats, in relation to Cd dose and time after injection. In the dose-response experiment Male Sprague-Dawley rats received a single subcutaneous (sc) injection of CdCl2 (1, 5 or 10 mumol/kg body weight) and were sacrificed 48 h after injection. A statistically significant decrease in luteinizing hormone (LH) receptor mRNA level in the testicular tissue was demonstrated at the highest dose (10 mumol/kg). In the temporal-response experiment rats were given 10 mumol/kg of CdCl2 sc and sacrificed 0.48, 4.8, 48 or 144 h after injection. LH receptor mRNA levels as well as cyclic adenosine monophosphate (cAMP) levels were found to be significantly lowered at 48 and 144 h. These observations of the mechanisms whereby Cd exerts its effect on the initial steps of testosterone biosynthesis are the first from in vivo experiments. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.