Effects of soy on the mammary glands of premenopausal female monkeys.
OBJECTIVE
To evaluate the interactive effects of dietary soy and menstrual cycle phase on breast proliferation, apoptosis, and sex steroid receptor expression in premenopausal female cynomolgus monkeys.


METHODS
Animals were randomized to receive diets with either casein lactalbumin or soy as the protein source for 12 months. Paired follicular and luteal mammary gland biopsies were taken before and after treatment and evaluated for epithelial proliferation and area, apoptosis, and sex steroid receptor expression.


METHODS
Academic research environment.


METHODS
Fifty-two adult female cynomolgus monkeys (Macaca fascicularis).


METHODS
Soy protein with the human equivalent of 129 mg/d of isoflavones.


METHODS
Breast proliferation and epithelial area.


RESULTS
Follicular and luteal assessments were taken on cycle day (+/- SE) 5.3 +/- 0.1 and 22.0 +/- 0.1, respectively. Serum E2, serum P, breast proliferation, and vaginal maturation were significantly higher in the luteal vs. follicular phase. Soy treatment resulted in significantly higher serum isoflavone concentrations compared with the casein lactalbumin group but did not significantly affect breast proliferation, epithelial area, apoptosis, or progesterone receptor expression; uterine size; or vaginal maturation in either the follicular or luteal phase.


CONCLUSIONS
Results indicate that dietary levels of soy intake have no detectable hormonal effects on the premenopausal breast.
Wood
Charles E
CE
Section on Comparative Medicine, The Comparative Medicine Clinical Research Center, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157-1040, USA. chwood@wfubmc.edu
Kaplan
Jay R
JR
Stute
Petra
P
Cline
J Mark
JM
D000284:Administration, Oral; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D004785:Environmental Pollutants / Q000633:toxicity*; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D005260:Female; D012739:Gonadal Steroid Hormones / Q000378:metabolism; D008252:Macaca fascicularis; D008321:Mammary Glands, Animal / Q000187:drug effects / Q000502:physiology*; D008597:Menstrual Cycle / Q000187:drug effects / Q000502:physiology*; D017697:Premenopause / Q000187:drug effects / Q000502:physiology*; D011980:Receptors, Progesterone / Q000378:metabolism*; D030262:Soybean Proteins / Q000008:administration & dosage*; D014018:Tissue Distribution
D004785:Environmental Pollutants; D012739:Gonadal Steroid Hormones; D011980:Receptors, Progesterone; D030262:Soybean Proteins