The occurrence of various serine proteinases and serine proteinases inhibitors (SERPINs) was investigated by RT-PCR in whole testes of 1-, 3-, and 8-wk-old mice in crude and enriched germ cell fractions, mouse Leydig tumor cells (mLTC-1), and primary cultures of 3- and 8-wk-old enriched fractions of Leydig cells and 3-wk-old Sertoli cells. New members were identified in the testis protease repertoire. Within the Leydig repertoire, a PCR product was found for plasminogen activators urokinase plasminogen activator (uPA) and tissue plasminogen activator (8-wk-old cells), matriptase-2 (mLTC-1), kallikrein-21, SERPINA5, SERPINB2 (primary cultures), and serine peptidase inhibitor Kunitz type 2 (SPINT2). The gonadotropin regulation was explored by semiquantitative RT-PCR, using steroidogenic acute regulatory protein (StAR) as a positive control. Matriptase-2, kallikrein-21, SPINT2, and SERPINA5 were down-regulated, whereas uPA and its receptor were up-regulated by human chorionic gonadotropin (hCG) via cAMP in the mLTC-1 cells. Positive effects were observed transiently after 1-8 h of hCG exposure, and negative effects, first evidenced after 6 h, lasted 48 h. The hCG-induced effects were confirmed in primary cultures. In addition, SERPINB2 was augmented by hCG in primary cultures. Addition of either trypsin or protease inhibitors did not alter the hCG-induced surge of StAR. Because hCG regulated proteases and SERPINs (whereas testosterone did not), it could alter the proteolytic balance of Leydig cells and consequently the metabolism of extracellular matrix components. Therefore, even though a direct interplay between the early hCG-induced surge of uPA and StAR is unlikely, our data together with the literature suggest that extracellular matrix proteins alter Leydig cell steroidogenesis.

2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and dioxin-like compounds are widely encountered toxic substances suspected of interfering with the endocrine systems of humans and wildlife, and of contributing to the loss of fertility. In this study, we determined the changes in testicular gene expression caused by in utero exposure to TCDD along with the intra-testicular testosterone levels, epididymal sperm reserves, daily sperm production (DSP) and testis histology. To this purpose, female pregnant Sprague–Dawley rats orally received TCDD (10, 100 or 200 ng/kg body weight) or vehicle at embryonic day 15, and the offspring was killed throughout development. Hepatic Cyp1a1 gene expression was measured in the offspring to confirm the exposure to TCDD. The gross histology of the testes and intra-testicular testosterone levels were normal among the studied groups. Sperm reserves were altered in 67-day-old rats of the TCDD-200 group, but not in 145-day-old animals or in the other TCDD-exposed groups. Nonetheless, fertility was not altered in males of the TCDD-200 group, and the F2 males generated had normal sperm reserves and DSP. Microarray analysis permitted the identification of eight differentially expressed genes in the 4-week-old testes of the TCDD-200 compared with that of the control group (cut-off value ± 1.40), including the down-regulated chemokine Ccl5/Rantes. Inhibition of Ccl5/Rantes gene expression was observed throughout development in the TCDD-200 group, and at 67 and 145 days in the TCDD-100 group (animals of younger ages were not examined). Ccl5/Rantes gene expression was mostly confined in Leydig cells. F2 males generated from males of the TCDD-200 group had normal levels of Ccl5/Rantes in testis and Cyp1a1 in liver, which might indicate that Ccl5/Rantes is a marker of TCDD exposure in testis such as Cyp1a1 in liver. In conclusion, we demonstrated a decrease in Ccl5/Rantes RNA levels and a transitory decline in sperm reserves in the testes of rats of TCDD-dosed dams.