Anabolic effect of parathyroid hormone is not modified by supplementation with insulinlike growth factor I (IGF-I) or growth hormone in aged female rats fed an energy-restricted or ad libitum diet.
Anabolic effect of parathyroid hormone is not modified by supplementation with insulinlike growth factor I (IGF-I) or growth hormone in aged female rats fed an energy-restricted or ad libitum diet.
复制标题
在能量限制或随意饮食的老年雌性大鼠中，补充胰岛素样生长因子 I (IGF-I) 或生长激素不会改变甲状旁腺激素的合成代谢作用。
DOI：
10.1016/8756-3282(94)00030-4
复制
发表时间：
1995
期刊：
影响因子：
4.1
通讯作者：
Hock,JM
中科院分区：
文献类型：
--
作者：
Gunness,M;Hock,JM
体内PTH通过刺激骨形成增加骨量，体外IGF-I部分介导PTH对胶原合成的刺激作用。本研究的目的是确定衰老大鼠的甲状旁腺激素的合成代谢作用是否因能量限制（ER）饮食而减弱，其中IGF-1水平已被证明降低，以及生长激素或IGF-1是否改变了骨骼对甲状旁腺激素的反应。2株18-24月龄雌性大鼠，自断奶以来，分别饲喂任意量（AL）或60% ER饲粮，分别皮下注射8 μg/100 g体重的hPTH 1-34或与生长激素（0.1 mg/100 g体重）联合皮下注射，每天2次，连续24或32 d。另外，er喂养大鼠每天2次在SC中添加60 μg/100 g体重的rhIGF-1，并给予PTH和/或GH治疗，持续12天。pth组大鼠腰椎骨体积（BV/TV）、骨矿物质堆积率（MAR）、骨形成率（BFRBS）、胫骨骨矿物质含量（BMC）等组织形态学指标均升高。BV在32 d （p < 0.01）和24 d （p < 0.05）显著升高，12 d （NS）无显著升高。矿化表面（MS/BS）和MAR的显著增加导致单独治疗PTH或GH的BFR增加2.9 - 3.6倍（p < 0.01）。这些增加与ER饮食无关，并且不受IGF-1或GH的影响。虽然ER大鼠体重减轻，但股骨长度不受影响，血清化学值在大鼠的生理范围内。总之，无论饮食如何，PTH通过刺激老年大鼠的骨形成来增加骨量，补充生长激素或IGF-I并没有改变骨对PTH的反应。
PTH increases bone mass by stimulating bone formation in vivo, and IGF-I partially mediates the stimulatory effect of PTH on collagen synthesis in vitro. The objectives of this study were to determine if the anabolic effect of PTH in aged rats was diminished by an energy-restricted (ER) diet in which IGF-I levels have been shown to be decreased, and if GH or IGF-1 modified the bone response to PTH. Two strains of aged female rats, 18–24 months, fed either ad libitum (AL) or 60% ER diets since weaning, were treated subcutaneously (SC) with 8 μg/100 g body weight hPTH 1–34 alone or in combination with GH given SC as 0.1 mg/100 g body weight twice daily for 24 or 32 days. Additional ER-fed rats were supplemented SC with 60 μg/100 g body weight rhIGF-1 twice daily and treated with PTH and/or GH for 12 days. Histomorphometric indices of bone volume (BV/TV), mineral apposition rate (MAR) and bone formation rate (BFRBS) in lumbar vertebrae and bone mineral content (BMC) of tibia increased in all PTH-treated rats. BV significantly increased after 32 (p < 0.01) or 24 (p < 0.05) days, but not 12 days (NS). Significant increases in mineralizing surfaces (MS/BS) and MAR resulted in 2.9–3.6-fold increases in BFR associated with PTH treatment alone or with GH (p < 0.01). These increases occurred regardless of an ER diet, and were not modified by IGF-1 or GH. Although ER rats weighed less, femur length was not affected and serum chemistry values were within the physiologic range for rats. In summary, PTH increased bone mass by stimulating bone formation in aged rats irrespective of diet, and supplementation with GH or IGF-I did not modify the response of bone to PTH.