Modulation of prolactin expression by xenoestrogens.
Xenoestrogens are widely used environmental chemicals that have recently been under scrutiny because of their possible role as endocrine disrupters. Among them are endosulfan and chlordane, two persistent insecticides suspected to act as estrogens in living organisms. To test and better understand the potential estrogenic activity of these chemicals, we used a pituitary cell line (GH(3)) known to respond to estrogens by increasing its secretion of prolactin (PRL), a hormone that is well known for its many physiological functions, especially in fetal growth, development, and reproduction. We measured the levels of PRL secretion and PRL mRNA transcription using immunometric tests, Northern blots, and relative quantitative RT-PCR. We also employed the XTT proliferation assay to compare the growth of GH(3) cells stimulated with 17-beta estradiol and endosulfan or chlordane. Our results show that endosulfan and chlordane are able to induce a substantial increase of PRL expression while these two chemicals do not increase cell growth. Together, our results suggest that endosulfan and chlordane could indeed modulate an estrogen-inducible gene such as PRL, possibly acting via second messenger-mediated cellular mechanisms instead of solely competing with estrogens for the nuclear estrogen receptor sites.
Rousseau
Joël
J
Department of Biochemistry, Université du Québec à Trois-Rivières, Trois-Rivières, Québec G9A 5H7, Canada.
Cossette
Louis
L
Grenier
Sonya
S
Martinoli
Maria-Grazia
MG
D015152:Blotting, Northern; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002706:Chlordan / Q000494:pharmacology; D004726:Endosulfan / Q000494:pharmacology; D004958:Estradiol / Q000494:pharmacology; D004968:Estrogens, Non-Steroidal / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects*; D007700:Kinetics; D010902:Pituitary Gland / Q000378:metabolism*; D011388:Prolactin / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction
D004968:Estrogens, Non-Steroidal; D012333:RNA, Messenger; D002706:Chlordan; D004958:Estradiol; D011388:Prolactin; D004726:Endosulfan