[Effects of lactational exposure to soy isoflavones on steroid receptor expression in neonate rat ovaries].
OBJECTIVE
To study the effects of lactational exposure to soy isoflavones (SIF) on ovary development in neonate rats.


METHODS
Virgin Sprague-Dawley female and male rats were fed with soy and alfalfa free diets (SAFD). The pregnant rats were randomly divided into six groups with seven animals in each group. Dams in different treatment groups received 0, 10, 50, 100, 150 and 200mg/kg bw of SIF from postnatal day 5 to 10 (PND5-10) by gavage, respectively. On PND11, female litters were killed and ovaries were removed for pathological evaluation and detection of estrogen receptor (ER), andron receptor (AR), progesterone receptor (PR), proliferating cell nuclear antigen (PCNA) protein expression by immunohistochemistry as well as ER, AR, PR mRNA expression by RT-PCR.


RESULTS
The ratios of ovary weight to body weight increased significantly in 100, 150 and 200 mg/kg bw groups than that in control group. And the ovary follicles developed more quickly in offsprings exposed to SIF. In 150 and 200 mg/kg bw groups, ER, PCNA protein and ER mRNA expression in ovaries increased significantly, while PR mRNA expression decreased significantly. Other receptor expressions had no significant difference from the control group.


CONCLUSIONS
Lactational exposure to soy isoflavones could induce adverse effects on ovary development in neonate rats, which mechanisms may, at least, partically involved with modification of mRNA transcription for ER and PR.
Li
Li
L
Institute for Nutrition and Food Safety, Chinese Centre for Disease Control and Prevention, Beijing 100050, China.
Zhang
Xiaopeng
X
Zhang
Wenzhong
W
Song
Yan
Y
D000818:Animals; D000831:Animals, Newborn; D005260:Female; D007529:Isoflavones / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D007774:Lactation; D018811:Maternal Exposure / Q000009:adverse effects*; D010053:Ovary / Q000254:growth & development*; D011247:Pregnancy; D018809:Proliferating Cell Nuclear Antigen / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011960:Receptors, Estrogen / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D013025:Glycine max / Q000737:chemistry
D007529:Isoflavones; D018809:Proliferating Cell Nuclear Antigen; D012333:RNA, Messenger; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone