Reproductive toxicity and pharmacokinetics of di-n-butyl phthalate (DBP) following dietary exposure of pregnant rats.
Most rodent developmental toxicity studies of dibutylphthalate (DBP) have relied on bolus gavage dosing. This study characterized the developmental toxicity of dietary DBP. Pregnant CD rats were given nominal doses of 0, 100, or 500 mg DBP/kg/day in diet (actual intake 0, 112, and 582 mg/kg/day) from gestational day (GD) 12 through the morning of GD 19. Rats were killed 4 or 24 hr thereafter. DBP dietary exposure resulted in significant dose-dependent reductions in testicular mRNA concentration of scavenger receptor class B, member 1; steroidogenic acute regulatory protein; cytochrome P450, family 11, subfamily a, polypeptide 1; and cytochrome P450 family 17, subfamily a, polypeptide 1. These effects were most pronounced 4 hr after the end of exposure. Testicular testosterone was reduced 24 hr post-exposure in both DBP dose groups and 4 hr after termination of the 500-mg DBP/kg/day exposure. Maternal exposure to 500 mg DBP/kg/day induced a significant reduction in male offspring's anogenital distance indicating in utero disruption of androgen function. Leydig cell aggregates, increased cord diameters, and multinucleated gonocytes were present in DBP-treated rats. Monobutyl phthalate, the developmentally toxic metabolite of DBP, and its glucuronide conjugate were found in maternal and fetal plasma, amniotic fluid, and maternal urine. Our results, when compared to previously conducted gavage studies, indicate that approximately equal doses of oral DBP exposure of pregnant rats, from diet or gavage, result in similar responses in male offspring.
Struve
Melanie F
MF
CIIT at The Hamner Institutes for Health Sciences, 6 Davis Drive, P.O. Box 12137, Research Triangle Park, NC 27709-2137, USA.
Gaido
Kevin W
KW
Hensley
Janan B
JB
Lehmann
Kim P
KP
Ross
Susan M
SM
Sochaski
Mark A
MA
Willson
Gabrielle A
GA
Dorman
David C
DC
D000284:Administration, Oral; D000653:Amniotic Fluid / Q000737:chemistry; D000726:Androgen Antagonists / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000633:toxicity*; D000818:Animals; D001711:Biotransformation; D001835:Body Weight / Q000187:drug effects; D003993:Dibutyl Phthalate / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D005837:Genitalia, Male / Q000187:drug effects / Q000196:embryology / Q000473:pathology; D005865:Gestational Age; D020719:Glucuronides / Q000032:analysis / Q000097:blood / Q000493:pharmacokinetics / Q000652:urine; D008297:Male; D010795:Phthalic Acids / Q000032:analysis* / Q000097:blood / Q000652:urine; D011247:Pregnancy; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D051122:Scavenger Receptors, Class B / Q000187:drug effects; D013256:Steroids / Q000096:biosynthesis; D013737:Testis / Q000187:drug effects / Q000196:embryology / Q000378:metabolism / Q000473:pathology; D013739:Testosterone / Q000096:biosynthesis
D000726:Androgen Antagonists; D020719:Glucuronides; D010795:Phthalic Acids; C495125:Scarb1 protein, rat; D051122:Scavenger Receptors, Class B; D013256:Steroids; D003993:Dibutyl Phthalate; D013739:Testosterone; C028577:monobutyl phthalate