Short-term neonatal/prepubertal exposure of dibutyl phthalate (DBP) advanced pubertal timing and affected hypothalamic kisspeptin/GPR54 expression differently in female rats.
Dibutyl phthalate (DBP) had been widely used and its exposure in children has been thought to be one of the reasons causing a trend of advanced pubertal timing in girls. Puberty starts from hypothalamic gonadotropin-releasing hormone release which is controlled by many factors including neurotransmitter kisspeptin and its receptor GPR54. These neural organization or reorganization happens in hypothalamus during neonatal or prepubertal period which may be two target windows of DBP exposure. The present study was designed to determine: (1) the difference between the effects of neonatal and prepubertal DBP exposure on female pubertal timing; (2) whether kisspeptin/GPR54 expression in hypothalamus would respond to neonatal and prepubertal DBP exposure differently. Female Sprague-Dawley rats were exposed by subcutaneous injection of 0.5, 5 and 50mg/kg DBP during Postnatal day (P)1-5 (neonatal) or P26-30 (prepubertal). Physiological data demonstrated that both neonatal and prepubertal DBP exposure could advance pubertal timing significantly accompanied by irregular estrous cycles but only a little gonadal impairment. Exposure-period-related difference was found significant with prepubertal exposure groups having longer estrous cycle duration, heavier at vaginal opening and having higher serum estradiol level compared with neonatal exposure groups. Molecular data showed an up-regulated trend in kisspeptin mRNA and immunoreactivity levels of hypothalamic area arcuate but a down-regulation in GPR54 mRNA expression after P1-5 DBP treatment. In P26-30 groups, kisspeptin mRNA and immunoreactivity levels tended to be lower after DBP treatment. These results demonstrated small dose of DBP could induce earlier pubertal timing in females and both neonatal and prepubertal periods were critical windows for DBP exposure.
Key Laboratory of Reproductive Medicine, School of Public Health, Institute of Toxicology, Nanjing Medical University, Nanjing 210029, China.
Jialei
J
Hu
Guizhen
G
Du
Wei
W
Zhang
Hongyu
H
Huang
Danni
D
Chen
Di
D
Wu
Xinru
X
Wang
D001003:Anal Canal / Q000033:anatomy & histology / Q000187:drug effects; D000818:Animals; D000831:Animals, Newborn; D001835:Body Weight / Q000502:physiology; D003993:Dibutyl Phthalate / Q000633:toxicity*; D030762:Estrous Cycle / Q000187:drug effects; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D005835:Genitalia / Q000033:anatomy & histology / Q000187:drug effects; D012739:Gonadal Steroid Hormones / Q000097:blood; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism*; D007150:Immunohistochemistry; D008297:Male; D009929:Organ Size / Q000187:drug effects / Q000502:physiology; D010053:Ovary / Q000187:drug effects / Q000254:growth & development / Q000473:pathology; D011247:Pregnancy; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D043562:Receptors, G-Protein-Coupled / Q000096:biosynthesis*; D000074502:Receptors, Kisspeptin-1; D012741:Sexual Maturation / Q000187:drug effects* / Q000502:physiology*; D014621:Vagina / Q000187:drug effects / Q000254:growth & development
D012739:Gonadal Steroid Hormones; C492247:Kiss1r protein, rat; D043562:Receptors, G-Protein-Coupled; D000074502:Receptors, Kisspeptin-1; D003993:Dibutyl Phthalate
ARC; AVPV; Arcuate; DBP; Kisspeptin/GPR54; Neonatal; Prepubertal; Puberty onset; anterior ventral periventricular; arcuate; dibutyl phthalate