The endocrine disrupters butyl benzyl phthalate and bisphenol A increase the expression of progesterone receptor messenger ribonucleic acid in the preoptic area of adult ovariectomized rats.
Butyl benzyl phthalate (BBP) and bisphenol A (BPA), so-called endocrine disrupters, are known to mimic the action of estrogens: they are thus liable to influence reproductive functions. Since little is known about their action on gene expression in the adult hypothalamus, we examined the effects of these chemicals on the expression of estrogen-regulated mRNAs, i.e., progesterone receptor (PR) mRNA, preproenkephalin (PPE) mRNA and neurotensin (NT) mRNA, in the hypothalamus and pituitary of adult female rats. Two weeks after ovariectomy, rats were subcutaneously injected with 10 mg BBP, 10 mg BPA, or 10 microg 17 beta-estradiol (E(2)) in sesame oil, or with sesame oil alone as a control. Twenty-four hours after the injection, tissues including the preoptic area (POA), mediobasal hypothalamus (MBH) and anterior pituitary were collected. Northern blot revealed that injection of E(2) resulted in expected changes, i.e., significant increases in PR mRNA in the POA, MBH and anterior pituitary, and in PPE mRNA in the MBH. We also found that injection of BPA significantly increased PR mRNA in the POA and anterior pituitary, while injection of BBP increased PR mRNA in the POA and anterior pituitary, although the increase in the anterior pituitary was not significant. No significant effect of E(2), BPA, or BBP on NT mRNA in the POA was detected. The present study demonstrates that the two endocrine disrupters BPA and BBP can increase the expression of PR mRNA in the POA of adult ovariectomized rats.
Funabashi
T
T
Department of Physiology, Yokohama City University School of Medicine, Yokohama, Japan. toshiya@med.yokohama-cu.ac.jp
Kawaguchi
M
M
Kimura
F
F
D000818:Animals; D001559:Benzhydryl Compounds; D004745:Enkephalins / Q000096:biosynthesis / Q000235:genetics; D004958:Estradiol / Q000494:pharmacology*; D004968:Estrogens, Non-Steroidal / Q000494:pharmacology; D005260:Female; D009496:Neurotensin / Q000096:biosynthesis / Q000235:genetics; D010052:Ovariectomy; D010636:Phenols / Q000494:pharmacology*; D010795:Phthalic Acids / Q000494:pharmacology*; D011301:Preoptic Area / Q000187:drug effects* / Q000378:metabolism; D011498:Protein Precursors / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011980:Receptors, Progesterone / Q000096:biosynthesis / Q000235:genetics; D000098826:Bisphenol A Compounds
D001559:Benzhydryl Compounds; D004745:Enkephalins; D004958:Estradiol; D004968:Estrogens, Non-Steroidal; D009496:Neurotensin; D010636:Phenols; D010795:Phthalic Acids; D011498:Protein Precursors; D012333:RNA, Messenger; D011980:Receptors, Progesterone; C033660:preproenkephalin; C006780:bisphenol A; D000098826:Bisphenol A Compounds; C027561:butylbenzyl phthalate