Mammary gland differentiation by early life exposure to enantiomers of the soy isoflavone metabolite equol
Division of Pathology and Laboratory Medicine, Cincinnati Children's Hospital Medical Center and the Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA.Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association (Impact Factor: 2.9). 11/2010; 48(11):3042-50. DOI: 10.1016/j.fct.2010.07.042
The role of soy in reducing breast cancer risk has been suggested to be associated with early exposure to isoflavones, which alter mammary gland morphology. The objective of the study was to determine the effect of dietary exposure to the enantiomers of a key soy isoflavone metabolite, equol, on mammary gland development and later chemoprotection using the DMBA-induced animal model of breast cancer. Animals were exposed to S-(-)equol or R-(+)equol (250 mg/kg diet) during the neonatal (0-21 days) or prepubertal (21-35 days) periods only. Histological evaluation of the mammary glands showed that both enantiomers fed neonatally via the dam led to significant precocial mammary gland differentiation. By day 50, early S-(-)equol or R-(+)equol exposure resulted in a decrease in immature terminal end structures and an increase in mature lobules, suggesting an early 'imprinting' effect. Despite these morphological changes to the mammary gland, neonatal and prepubertal exposure to equol had no long-term chemoprevention against mammary tumors induced by DMBA, although for R-(+)equol there was a trend to delaying tumor formation. In summary, early exposure to equol was not chemopreventive, but neither did it increase tumor formation in response to DMBA, suggesting exposure in early life does not influence breast cancer risk.
Conference Paper: A Radar Altimeter with Synthetic Aperture Processing[Show abstract] [Hide abstract]
ABSTRACT: The design of a radar altimeter, using synthetic aperture processing to achieve high spatial resolution in measurements of land topography, is described. The radar incorporates several novel features, such as digital generation of the transmit and deramp local oscillator waveforms, which allow very high processing gain to be achieved. Examples of experimental results obtained with the altimeter are also presented.Microwave Conference, 1989. 19th European; 10/1989
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ABSTRACT: We investigated whether maternal exposure during pregnancy to cow's milk containing endogenous estrogens and insulin-like growth factor 1 (IGF-1) and either high or low levels of isoflavones from dietary legumes (HIM and LIM, respectively) affected carcinogen-induced mammary carcinogenesis in female rat offspring. Pregnant Sprague-Dawley rats were given HIM, LIM, or tap water (control) from gestational day (GD) 11 until birth; hereafter all rats received tap water. Mammary tumorigenesis was induced by administrating 7,12-dimethylbenz[a]anthracene (DMBA) on postnatal day 50. No differences in maternal serum estradiol (P = 0.19) and IGF-1 levels (P = 0.15) at GD 19 or birth weight among the milk and water groups were seen, but estradiol, and IGF-1 levels and birth weight were numerically higher in the LIM group than in the HIM group. Puberty onset occurred earlier in the LIM offspring than in controls (P = 0.03). Although the high isoflavone content seemed to prevent the effect on circulating estradiol and IGF-1 levels and advanced puberty onset seen in the LIM group, HIM increased DMBA-DNA adducts in the mammary gland and tended to increase mammary tumorigenesis. In contrast, offspring exposed to LIM in utero, did not exhibit increased breast cancer risk, despite having higher estradiol and IGF-1 environment and consequently earlier puberty onset. These results indicate that the phytochemical content in the cow's milk, consumed by a pregnant dam, determines how milk affects the offspring.Cancer Prevention Research 04/2011; 4(5):694-701. DOI:10.1158/1940-6207.CAPR-10-0220 · 4.44 Impact Factor
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