MaRGA Meeting, 2004: Abstracts

21: Physiology and Immunology

Bone Mineral Density During Lactation in Common Marmosets

R.A. Power¹, D.G. Layne², D. Smucny², and S.D. Tardif²

Affiliation: ¹Pennington Biomedical Research Center, Baton Rouge, LA, and ²Southwest National Primate Research Center, San Antonio, TX

A significant decline in bone mineral density (BMD) has been observed during lactation in women and Old World monkeys; calcium supplementation does not alter this effect in women. Our study examines the effects of lactation on maternal bone in marmosets fed a calcium replete (1.2%; CCL) or deplete (0.3%; CRL) diet. Serum and urine samples are collected for biochemical markers of bone and DEXA is performed to measure BMD at baseline (non-pregnant; NP), 22 days post-partum (d22pp), 60 days post-partum (d60pp), and 94 days post-partum (d94pp). Fluorescent labels are administered at NP and d14-d22pp, and bones are collected at d94pp for histomorpometry. Data for 8 subjects have been collected (3 CCL, 5 CRL; 2 twin litters in each group). Statistical group comparisons are not feasible at this time due to sample size. A significant decrease in BMD during lactation compared to NP was observed for the combined 8 subjects, suggesting maternal bone loss during lactation in common marmosets. No significant difference was observed between NP and lactating mineral apposition rates for the 8 subjects. One CRL subject exhibited significant osteoid with a mineralization defect indicative of histological osteomalacia, suggesting that a low calcium diet during a time of increased mineral demand may lead to metabolic bone disease in marmosets. In addition, NP females (n=13) were compared to males (n=11). A trend toward higher BMD in females (comparable age) was observed; this is likely due to greater body weight in the females, as BMD and body weight are significantly correlated.