Exposure to octylphenol increases basal testosterone formation by cultured adult rat Leydig cells

Does 4-tert-octylphenol affect estrogen signaling pathways in bank vole Leydig cells and tumor mouse Leydig cells in vitro?

Primary Leydig cells obtained from bank vole testes and the established tumor Leydig cell line (MA-10) have been used to explore the effects of 4-tert-octylphenol (OP). Leydig cells were treated with two concentrations of OP (10(-4) M, 10(-8) M) alone or concomitantly with anti-estrogen ICI 182,780 (1 μM). In OP-treated bank vole Leydig cells, inhomogeneous staining of estrogen receptor α (ERα) within cell nuclei was found, whereas it was of various intensity among MA-10 Leydig cells. The expression of ERα mRNA and protein decreased in both primary and immortalized Leydig cells independently of OP dose. ICI partially reversed these effects at mRNA level while at protein level abrogation was found only in vole cells. Dissimilar action of OP on cAMP and androgen production was also observed. This study provides further evidence that OP shows estrogenic properties acting on Leydig cells. However, its effect is diverse depending on the cellular origin.

Effect of nonylphenol on male reproduction: analysis of rat epididymal biochemical markers and antioxidant defense enzymes

The mechanism by which nonylphenol (NP) interferes with male reproduction is not fully elucidated. Therefore, the present study was conducted to evaluate the effect of NP on male reproductive organ's weight, sperm characteristics, and to elucidate the nature and mechanism of action of NP on the epididymis. Adult male Wistar rats were gavaged with NP, dissolved in corn oil, at 0, 100, 200 or 300mg/kg/day for 30 consecutive days. Control rats were gavaged with vehicle (corn oil) alone. Body weight did not show any significant change while, absolute testes and epididymides weights were significantly decreased. Sperm count in cauda and caput/corpus epididymides, and sperm motility was significantly decreased. Daily sperm production was significantly decreased in a dose-related manner. Sperm transit time in cauda epididymis was significantly decreased by 300mg/kg, while in the caput/corpus epididymis it was significantly decreased by 200 and 300mg/kg of NP. Plasma LDH was significantly increased while; plasma testosterone was significantly decreased in a dose-related pattern. In the epididymal sperm, NP decreased acrosome integrity, Δψm and 5'-nucleotidase activity. Hydrogen peroxide (H(2)O(2)) production and LPO were significantly increased in a dose-related pattern. The activities of SOD, CAT and GPx were significantly decreased in the epididymal sperm. In conclusion, this study revealed that NP treatment impairs spermatogenesis and has a cytotoxic effect on epididymal sperm. It disrupts the prooxidant and antioxidant balance. This leads oxidative stress in epididymal sperms of rat. Moreover, the reduction in sperm transit time may affect sperm quality and fertility potential.

Differential effects of nonylphenol on testosterone secretion in rat Leydig cells

Nonylphenol (NP), a final metabolite of nonylphenol polyethoxylate, has been reported to interfere with male reproduction. However, its mechanisms are not fully understood. In the present study, we examined the effects of NP on steroidogenesis of testosterone in rat Leydig cells. The testosterone concentrations in rat plasma were examined after intravenous injection of NP (100 microg/kg) at different time intervals. In addition, rat Leydig cells were challenged with different concentrations of NP (4.25-127.5 microM) to evaluate its influences on testosterone steroidogenesis. Administration of NP showed a decrease of hCG-induced plasma testosterone. Moreover, in vitro experiments revealed that NP (127.5 microM) alone stimulated testosterone release through increase of both protein levels and activities of the StAR and P450(SCC). In contrast, NP inhibited hCG-induced testosterone release in rat Leydig cells. The inhibitory effect was also observed after incubation of the Leydig cells in the presence of different precursors. These results suggested that NP had differential effects on testosterone synthesis.