Exposure of prepubertal female rats to inhaled di(2-ethylhexyl)phthalate affects the onset of puberty and postpubertal reproductive functions.
We evaluated the effects of inhaled di(2-ethylhexyl)phthalate (DEHP) on the onset of puberty and on postpubertal reproductive functions in prepubertal female rats. DEHP was administered by inhalation at doses of 0, 5, and 25 mg/m3 to groups of female rats for 6 h/day, 5 contiguous days/week from postnatal days (PNDs) 22 to 41 and to PND 84. The onset of puberty was determined by daily examination for vaginal opening (VO) and first estrous cycle. Reproductive function was evaluated by observing estrous cyclicity from PNDs 49 to 84. Upon completion of exposure, the rats were sacrificed at PND 42 and PNDs 85-88 during the diestrous stage. DEHP exposure advanced the age of VO and first estrous cycle, and serum cholesterol, luteinizing hormone, and estradiol levels were significantly elevated in the 25-mg/m3 DEHP group. Irregular estrous cycles were observed more frequently in DEHP-exposed rats, and serum cholesterol decreased in DEHP-exposed rats in adulthood; RT-PCR showed that the expression of aromatase mRNA, encoding a rate-limiting enzyme that catalyzes the conversion of testosterone to estradiol, was elevated in the 25-mg/m3 DEHP group. These data suggest that inhaled DEHP may advance the onset of puberty and alter postpubertal reproductive functions.
Ma
Mingyue
M
Department of Public Health, Hokkaido University Graduate School of Medicine, Kita 15, Nishi 7, Kita-ku, Sapporo 060-8638, Japan. mamingy@med.hokudai.ac.jp
Kondo
Tomoko
T
Ban
Susumu
S
Umemura
Tomohiro
T
Kurahashi
Norie
N
Takeda
Makoto
M
Kishi
Reiko
R
D000818:Animals; D001483:Base Sequence; D002784:Cholesterol / Q000097:blood; D017931:DNA Primers; D004051:Diethylhexyl Phthalate / Q000008:administration & dosage / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000097:blood; D004971:Estrus; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D015870:Gene Expression / Q000187:drug effects; D019570:Inhalation Exposure; D007986:Luteinizing Hormone / Q000097:blood; D010053:Ovary / Q000201:enzymology; D011247:Pregnancy; D051381:Rats; D017208:Rats, Wistar; D012098:Reproduction / Q000187:drug effects*; D012741:Sexual Maturation; D013739:Testosterone / Q000097:blood
D017931:DNA Primers; D013739:Testosterone; D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D002784:Cholesterol; D004051:Diethylhexyl Phthalate