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The selective estrogen receptor modulator, raloxifene: a segment II/III delivery study in rats
J Buelke-Sam1, I R Cohen, D Wierda
1Toxicology Research Laboratories, Lilly Research Laboratories, A Division of Eli Lilly and Company, Greenfield, Indiana 46140, USA. jb_s@lilly.com
Reproductive Toxicology (Elmsford, N.Y.)
|June 17, 1998
Summary
Raloxifene, a selective estrogen receptor modulator, caused dose-related maternal and developmental effects in rats, including parturition difficulties and reproductive system changes in offspring. These findings suggest estrogen antagonist activity.
Area of Science:
- Toxicology
- Reproductive Science
- Pharmacology
Background:
- Raloxifene is a selective estrogen receptor modulator (SERM) used for postmenopausal osteoporosis.
- Understanding its developmental and reproductive toxicity is crucial for therapeutic safety.
Purpose of the Study:
- To evaluate the reproductive and developmental toxicity of raloxifene in a rat model.
- To assess effects on maternal health, pregnancy, parturition, and F1 generation development and reproduction.
Main Methods:
- Pregnant rats received raloxifene (0, 0.1, 1, 10 mg/kg/d) from GD 6 to PD 20.
- Maternal parameters, pup survival, growth, development, immune function, and reproductive performance were assessed.
- Histological evaluations of reproductive organs were performed at various time points.
Main Results:
- Maternal toxicity included decreased body weight, food consumption, and parturition complications at higher doses.
- Offspring showed dose-related growth depression, delayed eye opening, and accelerated vaginal patency.
- Reproductive assessments revealed disrupted estrous cycles, reduced fertility, and uterine hypoplasia in high-dose females.
Conclusions:
- Raloxifene exhibits dose-dependent maternal and developmental toxicity in rats.
- Findings are consistent with raloxifene's estrogen antagonist activity.
- Potential risks to reproduction and development warrant consideration in clinical use.
