Non-human primates are frequently used to model human skeletal physiology. However, standard laboratory monkey chow provides significantly more calcium and vitamin D than the """"""""typical"""""""" American diet. To assess the effects of this calcium and vitamin D replete diet, we characterized measures of nutritional and skeletal status in adult and old female rhesus monkeys (adult premenopausal, age 11-25 years, n = 17; and postmenopausal, age 24-35 years, n = 10). Serum levels of calcium, creatinine, albumin, alkaline phosphatase, osteocalcin, parathyroid hormone (PTH), 25 hydroxyvitamin D, interleukin-6 (IL-6), estradiol (E2) and follicle stimulating hormone (FSH) were evaluated. Bone mineral density (BMD) was measured by dual energy x-ray absorptiometry at the lumbar spine and distal radius. Postmenopausal status was defined as the absence of menses for one year associated with elevated FSH and low E2 levels. In comparison to the premenopausal group, the postmenopausal animals had elevated serum IL-6 and osteocalcin levels (p < 0.05, unpaired t-test), but were not different in BMD at the spine or distal radius. No differences were observed in serum PTH, vitamin D concentration, or chemistry values. In conclusion; the """"""""age-related"""""""" reduction in vitamin D status and associated hyperparathyroidism commonly observed in humans was not found, likely due to high dietary intake of calcium and vitamin D in these animals. Although bone turnover was elevated in the postmenopausal group, we observed no difference in bone density. The lack of demonstrable E2-depletion bone loss is surprising and may reflect small sample size; however, these data support the hypothesis that """"""""age-related"""""""" osteoporosis is largely the result of inadequate nutrition.
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