Effects of lactational exposure to soy isoflavones on reproductive system in neonatal female rats.
To examine effects of lactational exposure to soy isoflavones on female reproductive system, soy isoflavones, 0 (control), 10, 50, 100, 150 or 200 mg/kg body weight, were administered to maternal rats by gavage daily during postnatal days 5-10. Ten female litters were killed on day 11. Uterine and ovary weights, serum oestradiol and progesterone concentrations, proliferating cell nuclear antigen, mRNA expressions of oestrogen receptor, androgen receptor and progesterone receptor in uterus or ovary were measured. When compared to the control group, litters in the 150 and 200 mg/kg body weight groups had significantly higher ovary and uterine weights (P < 0.05). Endometrial thickness was also significantly increased. Isoflavone-treated groups had increased proliferating cell nuclear antigen staining in comparison to the control group. Litters in the 50, 150 and 200 mg/kg body weight groups had significantly higher oestradiol concentration while lower progesterone concentrations than those in the control group (P < 0.05 or P < 0.01). All soy isoflavone-treated groups had androgen receptor mRNA expressions in ovary and uterus comparable to the control group. Progesterone receptor mRNA expression in the 150 and 200 mg/kg body weight groups was significantly lower than that in control group (P < 0.01). However, ovaries in the 150 and 200 mg/kg body weight groups had significantly higher oestrogen receptor mRNA expression while the uterus in these two treatment groups had significantly lower expressions, when compared to the control group (P < 0.05 or P < 0.01). In conclusion, lactational exposure to isoflavones could result in oestrogen-like actions on the reproductive system of neonate female rats, which mechanisms may be, at least, involved with modifications of hormone production and steroid receptor transcription in the reproductive system.
Department of Food Toxicology, Institute of Nutrition and Food Safety, Chinese Center for Disease Control and Prevention, Beijing, China. zhpliu@yahoo.com
Zhaoping
Z
Liu
Xiaopeng
X
Zhang
Li
L
Li
Wenzhong
W
Zhang
Wenming
W
Cui
Yan
Y
Song
Wei
W
Wang
Xudong
X
Jia
Ning
N
Li
Weixing
W
Yan
D000818:Animals; D000831:Animals, Newborn; D001835:Body Weight; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000097:blood; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D007529:Isoflavones / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D007774:Lactation; D008297:Male; D009929:Organ Size / Q000187:drug effects; D011374:Progesterone / Q000097:blood; D018809:Proliferating Cell Nuclear Antigen / Q000187:drug effects / Q000378:metabolism; D012333:RNA, Messenger / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D011960:Receptors, Estrogen / Q000187:drug effects / Q000378:metabolism; D011980:Receptors, Progesterone / Q000187:drug effects / Q000378:metabolism; D012098:Reproduction / Q000187:drug effects*; D013025:Glycine max / Q000737:chemistry
D007529:Isoflavones; D018809:Proliferating Cell Nuclear Antigen; D012333:RNA, Messenger; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D011374:Progesterone; D004958:Estradiol