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Changes in bone turnover during the menstrual cycle in cynomolgus monkeys
1Section on Comparative Medicine, Department of Pathology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, North Carolina 27157-1040, USA.
Calcified Tissue International
|February 10, 2000
Summary
Estrogen levels fluctuate during the menstrual cycle, impacting bone turnover markers. Bone resorption peaks when estrogen is lowest, supporting the hypothesis that estrogen reduces bone turnover.
Area of Science:
- Endocrinology
- Bone Biology
- Reproductive Science
Background:
- Estrogen deficiency at menopause increases bone turnover.
- Menstrual cycle fluctuations in 17beta-estradiol suggest potential cyclical changes in bone turnover.
- Previous human studies yielded inconsistent results due to confounding factors.
Purpose of the Study:
- To investigate cyclical changes in bone turnover markers throughout the menstrual cycle.
- To examine the relationship between serum 17beta-estradiol and bone biomarkers in a non-human primate model.
Main Methods:
- Seven intact female cynomolgus macaques were studied.
- Menstrual cycle staging via vaginal swabs.
- Weekly/biweekly blood and urine collection for analysis of 17beta-estradiol, progesterone, PTH, osteocalcin, BSAP, and urinary CrossLaps.
- Cosinor analysis to identify cyclical patterns.
Main Results:
- Serum osteocalcin, BSAP, and urinary CrossLaps showed significant cyclical patterns.
- Osteocalcin and CrossLaps were inversely correlated with 17beta-estradiol.
- Urinary CrossLaps decreased during the pre-ovulatory surge in estradiol.
- No significant rhythm detected for serum PTH.
Conclusions:
- Bone turnover markers exhibit cyclical changes throughout the menstrual cycle in cynomolgus macaques.
- Estrogen appears to suppress bone resorption, as evidenced by the inverse correlation between 17beta-estradiol and bone turnover markers.
- These findings support the hypothesis that estrogen plays a role in regulating bone turnover.
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