BONE AND MINERAL METABOLISM IN BLACKS AND WHITES

在这一竞争性更新中提出的调查的目的 应用是确定骨量增加和 骨骼形成率和周转率的下降发生在黑人和 导致或导致骨质疏松症的低发病率 以及其中的骨折，以调查更年期和 年龄对黑人骨和矿物质代谢的影响 黑人老年性或II型骨质疏松的发病机制。假说 需要调查的是：a)黑人的骨吸收率较低 而不是白种人，这是由于由 外周血单核细胞产生的骨吸收细胞因子减少 和骨细胞，并伴有骨骼反应减弱 甲状旁腺激素，b)黑人中较大的骨量不会导致 仅仅是由于骨骼重塑的减少，而是由于成骨细胞的改变 功能：所产生的生长因子的量的差异 成骨细胞或储存在骨中，它们的结合蛋白或一些 联合，c)绝经期雌激素产生的损失 黑人女性会导致骨吸收增强，而骨吸收是由 外周血单核细胞和成骨细胞分泌细胞因子的增加 并与骨吸收和骨丢失增加有关， 这些变化被Premarin逆转了，d)年迈的黑人无法 适应低钙饮食，因为与年龄相关的 肾脏产生1，25-二羟基维生素D，并在 骨骼重塑和，e)损害肾脏产生的比率 1，25-二羟基维生素D在老年人发病机制中的重要作用 黑人的骨质疏松症。这些研究的结果应该会提供新的 和有关骨质疏松症发病机制的有用信息 并可能导致可用于诊断的新方法， 疾病的治疗和预防。

The purpose of the investigations proposed in this competing renewal application is to determine the means by which increases in bone mass and decreases in rates of bone formation and turnover occur in blacks and contribute to or are responsible for the low incidence of osteoporosis and fractures in them, to investigate the effects of the menopause and aging on bone and mineral metabolism in blacks and to investigate the pathogenesis of senile or type II osteoporosis in blacks. The hypotheses to be investigated are a) that bone resorption rate is lower in blacks than in whites and results from altered osteoclast function caused by diminished production of bone-resorbing cytokines by peripheral monocytes and bone cells and is accompanied by diminished skeletal response to parathyroid hormone, b) that the greater bone mass in blacks results not only from a reduction in skeletal remodeling but from altered osteoblast function: differences in the amount of growth factors produced by osteoblasts or stored in bone, their binding proteins or some combination, c) that loss of estrogen production at the menopause in black women results in enhanced bone resorption that is caused by increased production of cytokines by peripheral monocytes and osteoblasts and is associated with increased bone resorption and bone loss and that these changes are reversed by Premarin, d) that aging blacks are unable to adapt to a low calcium diet because of an age-related decline in the renal production of 1,25- dihydroxyvitamin D and have increases in the rate of skeletal remodeling and, e) that impaired renal production of 1,25-dihydroxyvitamin D is important in the pathogenesis of senile osteoporosis in blacks. The results of these studies should provide new and useful information concerning the pathogenesis of osteoporosis in blacks and could lead to new methods that can be used for the diagnosis, treatment and prevention of the disease.