Placental endocrine disruption induced by cadmium: effects on P450 cholesterol side-chain cleavage and 3beta-hydroxysteroid dehydrogenase enzymes in cultured human trophoblasts.
We previously suggested that cadmium (Cd), an environmental toxicant and constituent of tobacco smoke, inhibits progesterone secretion in cultured human placental trophoblasts by inhibiting low-density lipoprotein receptor mRNA expression. In the current study, we investigated whether Cd also disrupts progesterone synthesis via P450 cholesterol side-chain cleavage (P450(scc)) and 3beta-hydroxysteroid dehydrogenase (3beta-HSD), enzymes that play important roles in placental steroidogenesis. Human cytotrophoblasts were purified by density gradient centrifugation and incubated in Dulbecco modified Eagle medium + 10% fetal bovine serum with 0, 5, 10, or 20 microM CdCl(2) for 96 h. Cells progressed to syncytiotrophoblastic maturity regardless of treatment. No differences (P > 0.05) in cell protein and lactate dehydrogenase activity were observed between untreated trophoblasts and those treated with CdCl(2). However, P450(scc) and 3beta-HSD mRNA transcript levels declined in a dose-dependent manner (P <0.05) in trophoblasts cocultured with 5, 10, or 20 microM CdCl(2). P450(scc) activity was similarly inhibited (P < 0.05) by CdCl(2) treatment, although 3beta-HSD activity was not significantly affected. Coculture with 8-bromo-cAMP enhanced progesterone secretion in untreated cultures but did not reverse the decline in progesterone secretion induced by CdCl(2) treatment. CdCl(2) failed to influence cAMP content in cultured cells. Collectively, results suggest that P450(scc) enzyme is another site at which Cd interferes with placental progesterone production. However, it is unlikely that an inhibition of cAMP is involved with the inhibition of progesterone biosynthesis by Cd in human trophoblasts.
Kawai
Motoyuki
M
Department of Obstetrics and Gynecology, Tulane University Health Sciences Center, 1430 Tulane Avenue, New Orleans, LA 70112-2699, USA.
Swan
Kenneth F
KF
Green
Amy E
AE
Edwards
Deborah E
DE
Anderson
Mary B
MB
Henson
Michael C
MC
D015096:3-Hydroxysteroid Dehydrogenases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000616:Aminoglutethimide / Q000494:pharmacology; D002104:Cadmium / Q000633:toxicity*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism; D018076:DNA, Complementary / Q000096:biosynthesis; D004702:Endocrine Glands / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D010920:Placenta / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D011247:Pregnancy; D011374:Progesterone / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014327:Trophoblasts / Q000201:enzymology / Q000502:physiology*
D018076:DNA, Complementary; D004791:Enzyme Inhibitors; D012333:RNA, Messenger; D002104:Cadmium; D000616:Aminoglutethimide; D015124:8-Bromo Cyclic Adenosine Monophosphate; D011374:Progesterone; D000242:Cyclic AMP; D015096:3-Hydroxysteroid Dehydrogenases; D007770:L-Lactate Dehydrogenase; D002786:Cholesterol Side-Chain Cleavage Enzyme