Delclos K.B et al, 2001

Negative Effects of Genistein Exposure on Pregnant Rats and Offspring

A study investigating the impact of genistein, a soy isoflavone, on pregnant rats and their offspring through dosed feeding found significant physiological changes compared to the control group :

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Effects on Pregnant Rats and Offspring Weight:​

• Pregnant rats exposed to genistein had reduced body weight and food intake before giving birth.

• Offspring rats, at 50 days post-birth, showed a significant decrease in body weight compared to the control group.

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Effects on Male Offspring:

• Ventral prostate weight was reduced in males at the highest dose (1,250 ppm).

• Pituitary gland weight (relative to body weight) was increased in both male and female offspring at the highest dose.

Pathohistological Changes in Offspring:

• Mammary gland hyperplasia (abnormal cell growth in milk-producing ducts and alveoli):

  • Observed in female rats at doses of 250–1,250 ppm.

  • Observed in male rats at doses above 25 ppm.

• Abnormal vaginal maturation: Found in female offspring at 625 and 1,250 ppm.

• Ovarian antral follicle abnormalities: Observed in female rats at 1,250 ppm.

• Sperm development issues:

  • Delayed or abnormal spermatogenesis in seminiferous tubules at 1,250 ppm.

  • Reduced sperm count in the epididymis at 625 and 1,250 ppm, though testicular spermatid head counts and epididymal spermatozoa counts remained unchanged compared to controls.

• Renal tubal mineralization (kidney abnormalities): Increased in both males and females at doses of 250 ppm and above.

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These findings suggest that genistein exposure during pregnancy may lead to developmental and reproductive changes in offspring, likely linked to estrogenic activity.

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Citation: Delclos KB, Bucci TJ, Lomax LG, Latendresse JR, Warbritton A, Weis CC, Newbold RR,Effects of dietary genistein exposure during development on male and female CD54(sprague-dawley) rats. Reprod.toxicol. (2001) 15: 647-663.