[Effects of mono(2-ethylhexyl) phthalate on testosterone biosynthesis in leydig cells cultured from the rat testis].
OBJECTIVE
To investigate the effects of mono(2-ethylhexyl) phthalate(MEHP), the primary metabolite of di(2-ethylhexyl) phthalate (DEHP), on testosterone biosynthesis in Leydig cells cultured from the Sprague Dawley rat testis.


METHODS
Based on the primary Leydig cell culture model, MEHP exposure groups involved control (0 micromol/L), 62.5, 125, 250, 500 and 1000 micromol/L. We observed mitochondria activity with the MTT method, measured the testosterone level with RIA and determined steroidogenesis acute regulatory protein (StAR) mRNA expression with RT-PCR.


RESULTS
After Leydig cells were exposed to MEHP for 24 hours, the activity of mitochondria enhanced evidently at 250 micromol/L and then declined markedly at 1000 micromol/L compared with the control group (P < 0.01). The testosterone level showed an increasing tendency in both basal and hCG-stimulated states with statistical significance at 250 and 500 micromol/L compared with the control group (P < 0.01). However, the expression of StAR mRNA appeared unchanged at 62.5, 125 or 250 micromol/L, but exhibited a decreasing tendency at 500 and 1000 micromol/L (P < 0.01).


CONCLUSIONS
ME- HP directly affected the activity of mitochondria and testosterone biosynthesis of the Leydig cells in vitro. StAR, the regulator of cholesterol transport into mitochondria, might not be responsible for the increase of testosterone biosynthesis induced by MEHP.
Zhu
Zheng-ping
ZP
Institute of Toxicology, Nanjing Medical University, Nanjing, Jiangsu 210029, China.
Wang
Yu-bang
YB
Song
Ling
L
Chen
Jian-feng
JF
Chang
Hebron C
HC
Wang
Xin-ru
XR
D000818:Animals; D002478:Cells, Cultured; D004051:Diethylhexyl Phthalate / Q000031:analogs & derivatives* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D007985:Leydig Cells / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D010750:Phosphoproteins / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013739:Testosterone / Q000096:biosynthesis*; D000098682:Steroidogenic Acute Regulatory Protein
D010750:Phosphoproteins; D012333:RNA, Messenger; D000098682:Steroidogenic Acute Regulatory Protein; D013739:Testosterone; D004051:Diethylhexyl Phthalate; C016599:mono-(2-ethylhexyl)phthalate