CALCIUM KINETICS IN PREGNANT AND LACTATING ADOLESCENTS

孕妇和哺乳期青少年的钙动力学

• 批准号: 2487936
• 负责人: Kimberly O O'Brien
• 金额: $ 14.57万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-01-15 至 2002-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2487936
• 关键词: adolescence (12-20); calcium; calcium metabolism; clinical research; estradiol; female; gastrointestinal nutrient absorption; hormone regulation /control mechanism; human subject; lactation; mother /embryo /fetus nutrition; normal ossification; nutrition related tag; osteocalcin; parathyroid hormones; pharmacokinetics; physiologic bone resorption; pregnancy; radionuclides; urinalysis; vitamin D

Adolescent pregnancy is a significant problem in the United States. Special nutritional concerns are present in this group to insure that optimal nutritional needs can be met by both the fetus and the growing adolescent. The additional nutritional demands of pregnancy may be of primary concern when the mother has not yet completed her linear growth and has not full achieved her peak bone mass. The aim of the proposed study is to address the impact of pregnancy and lactation on the efficiency of calcium absorption and rates of bone calcium deposition and resorption in adolescent non-Hispanic white and non-Hispanic black girls between the ages of 11-17 years. Fifteen girls from each group who intend to breastfeed their infants will participate in a longitudinal calcium kinetic study designed to address the efficiency of calcium absorption and rates of bone calcium turnover during both the third trimester of pregnancy (34-36 weeks of gestation) and during lactation (1-2 months post partum). All adolescents will be screened for positive predictors of lactation performance prior to the start of the study. In each kinetic study, girls will be admitted to the General Clinical Research Unit at Johns Hopkins Hospital. On the morning of each study, girls will consume a glass of milk containing a stable calcium isotope (46Ca), and following breakfast a second stable calcium isotope (42Ca) will be administered intravenously. Timed blood samples will be obtained for eight hours following the isotope dosing, and a complete 24 hour urine collection will be made. Additional spot urine samples will be collected for 5 days following each isotope study. To address the hormonal response to pregnancy and lactation, calcitropic hormones will be measured during each study using a fasting blood sample. Rates of bone calcium deposition and resorption in response to these physiological changes will be determined using multicompartmental modeling. These studies will provide novel information on the physiological alterations in calcium absorption and bone calcium turnover which occur to support both the increased calcium demands of adolescence and the calcium demands of pregnancy and lactation.

少女怀孕在美国是一个严重的问题。 这一群体存在特殊的营养问题，以确保 最佳的营养需求可以满足胎儿和生长 青春期。 怀孕的额外营养需求可能是 当母亲还没有完成她的线性生长时， 还没有达到她的峰值骨量 建议的目的 研究的目的是解决怀孕和哺乳对 钙吸收效率和骨钙沉积率 非西班牙裔白色和非西班牙裔黑人青少年中的骨吸收 11-17岁之间的女孩。 每组15个女孩 打算母乳喂养婴儿的人将参加一个 纵向钙动力学研究旨在解决效率 的钙吸收和骨钙周转率在这两个 妊娠晚期（妊娠34-36周）和 哺乳期（产后1-2个月）。 所有青少年都将接受筛查 对于泌乳性能的积极预测因素， 书房 在每次动力学研究中，女孩将被录取到一般 约翰霍普金斯医院临床研究部。 日上午 每项研究中，女孩们都会喝一杯牛奶， 钙同位素（46 Ca），以及早餐后的第二稳定钙 将静脉内施用同位素（42 Ca）。 定时血样 将在同位素给药后8小时内获得， 将收集完整的24小时尿液。 额外点尿 在每次同位素研究后，将收集样品5天。 到 解决对妊娠和哺乳的激素反应，促钙 在每项研究期间，将使用空腹血液测量激素。 sample. 骨钙沉积率和骨吸收率 这些生理变化将使用多室 建模这些研究将提供新的信息 钙吸收和骨钙的生理变化 发生的周转，以支持增加的钙需求， 青春期以及怀孕和哺乳期的钙需求。