Hohman E E, McCabe G P, Peacock M, Weaver C M
Department of Nutrition Science, Purdue University, 700 W. State Street, West Lafayette, IN, 47907, USA.
Osteoporos Int. 2014 Oct;25(10):2471-5. doi: 10.1007/s00198-014-2790-6. Epub 2014 Jun 27.
Urinary excretion of calcium tracers in labeled individuals decreases in response to antiresorptive therapy, providing a tool to rapidly screen potential therapies. Using teriparatide, we demonstrate in this study that anabolic therapy also decreases tracer excretion, confirming that this method can also be used to screen potential anabolic therapies.
Changes in urinary excretion of calcium tracers from a labeled skeleton may be a rapid and sensitive method to screen potential therapies for osteoporosis. This method has been used to screen antiresorptive therapies, but the effect of anabolic therapies on tracer excretion is unknown.
Eight-month-old female Sprague Dawley rats (n = 11) were given 50 μCi (45)Ca iv. After a 1-month equilibration period, baseline urinary (45)Ca excretion and total bone mineral content (BMC) were measured. Rats were then treated with 30 μg/kg teriparatide sc per day, a bone anabolic agent, for 80 days. Urine was collected throughout the study and analyzed for (45)Ca and total Ca, and BMC was measured at the beginning and end of the study.
Teriparatide decreased urinary (45)Ca excretion by 52.1 % and increased BMC by 21.7 %. The change in bone calcium retention as determined by the ratio of (45)Ca to total Ca excretion in urine from day 6 through 15 of teriparatide treatment was significantly correlated (p = 0.036) with the change in BMC after 80 days of teriparatide treatment.
Urinary excretion of calcium tracers from labeled bone is an effective method to rapidly screen potential anabolic therapies for osteoporosis.
接受抗吸收治疗后，标记个体中钙示踪剂的尿排泄量会降低，这为快速筛选潜在治疗方法提供了一种工具。在本研究中，我们使用特立帕肽证明，合成代谢疗法也会降低示踪剂排泄量，证实该方法也可用于筛选潜在的合成代谢疗法。
来自标记骨骼的钙示踪剂尿排泄量的变化可能是一种快速且灵敏的方法，用于筛选骨质疏松症的潜在治疗方法。该方法已用于筛选抗吸收疗法，但合成代谢疗法对示踪剂排泄的影响尚不清楚。
给8个月大的雌性斯普拉格-道利大鼠（n = 11）静脉注射50 μCi的（45）Ca。经过1个月的平衡期后，测量基线尿（45）Ca排泄量和总骨矿物质含量（BMC）。然后，大鼠每天皮下注射30 μg/kg的特立帕肽（一种骨合成代谢剂），持续80天。在整个研究过程中收集尿液，分析其中的（45）Ca和总钙，并在研究开始和结束时测量BMC。
特立帕肽使尿（45）Ca排泄量降低了52.1%，并使BMC增加了21.7%。在特立帕肽治疗的第6天至第15天，通过尿中（45）Ca与总钙排泄量之比确定的骨钙保留变化与特立帕肽治疗80天后的BMC变化显著相关（p = 0.036）。
标记骨中钙示踪剂的尿排泄是一种快速筛选骨质疏松症潜在合成代谢疗法的有效方法。
