Relative effects of PTH and dietary phosphorus on calcitriol production in normal and azotemic rats.
Relative effects of PTH and dietary phosphorus on calcitriol production in normal and azotemic rats.
复制标题
PTH 和膳食磷对正常和氮血症大鼠骨化三醇产生的相对影响。
作者：
S. Tallon;I. Berdud;A. Hernández;M. T. Concepción;Y. Almadén;A. Torres;A. Martín;A. Felsenfeld;P. Aljama;M. Rodríguez
在中度肾功能衰竭中，血清骨化三醇水平受到高PTH的刺激作用和磷潴留的抑制作用的影响。我们的目标是评估高 PTH 水平和增加膳食磷对正常大鼠 (N) 和中度肾衰竭大鼠 (Nx) 骨化三醇产生的相对影响。将正常大鼠和 Nx（3/4 肾切除术）大鼠分为两组：（1）具有完整甲状旁腺的大鼠（IPTG）和（2）使用微渗 Alzet 泵连续输注大鼠 1-34 PTH（0.022 微克/小时/100 g 体重）替代 PTH 的甲状旁腺切除大鼠（PTHR）。为了测试膳食磷的影响，大鼠接受中磷（MPD，0.6％P）或高磷（HPD，1.2％）饮食14天。实验设计包括用 IPTG 或 PTHR 配对喂养 N 和 Nx 大鼠。饲喂 MPD 的 N 只大鼠的血清骨化三醇和 PTH 水平分别为 69 +/- 3 和 40 +/- 5 pg/ml。在进行 MPD 的 Nx 大鼠中，只有在不允许发生甲状旁腺功能亢进的情况下，血清骨化三醇水平才会下降（Nx-IPTG-MPD 组和 Nx-PTHR-MPD 组分别为 76 +/- 4 与 62 +/- 4 pg/ml，P < 0.05）。即使在 HPD 的 N 只大鼠中，也需要高 PTH 水平（N-IPTG-HPD 组中为 67 +/- 8 pg/ml）才能维持正常的血清骨化三醇水平（Nx-IPTG-HPD 和 Nx-PTHR-HPD 组中分别为 69 +/- 4 与 56 +/- 6 pg/ml；P < 0.05）。在接受 HPD 的 Nx 大鼠中，继发性甲状旁腺功能亢进症（Nx-IPTG-HPD 组中为 286 +/- 19 pg/ml）的发生阻止了血清骨化三醇水平的下降（68 +/- 7 pg/ml）。相比之下，Nx-PTHR-HPD 组的血清骨化三醇水平较低（52 +/- 4 pg/ml，P < 0.05），其内源性 PTH 产生的适应性增加被剥夺。总之，我们在大鼠中的结果表明，在中度肾衰竭中，升高的 PTH 水平可以维持骨化三醇的产生并克服磷潴留的抑制作用。
In moderate renal failure, the serum calcitriol level is influenced by the stimulatory effect of high PTH and the inhibitory action of phosphorus retention. Our goal was to evaluate the relative effect that high PTH levels and increased dietary phosphorus had on calcitriol production in normal rats (N) and rats with moderate renal failure (Nx). Normal and Nx (3/4 nephrectomy) rats were divided into two groups: (1) rats with intact parathyroid glands (IPTG) and (2) parathyroidectomized rats in which PTH was replaced (PTHR) by the continuous infusion of rat 1-34 PTH, 0.022 microgram/hr/100 g body wt, using a miniosmotic Alzet pump. To test the effect of dietary phosphorus, rats received either a moderate (MPD, 0.6% P) or a high phosphorus (HPD, 1.2%) diet for 14 days. The experimental design included pair-fed N and Nx rats with either IPTG or PTHR. Serum calcitriol and PTH levels in N rats fed a MPD were 69 +/- 3 and 40 +/- 5 pg/ml, respectively. In Nx rats on a MPD, serum calcitriol levels decreased only if hyperparathyroidism was not allowed to occur (76 +/- 4 vs. 62 +/- 4 pg/ml in Nx-IPTG-MPD and Nx-PTHR-MPD groups respectively, P < 0.05). Even in N rats on a HPD, high PTH levels (67 +/- 8 pg/ml in the N-IPTG-HPD group) were required to maintain normal serum calcitriol levels (69 +/- 4 vs. 56 +/- 6 pg/ml in Nx-IPTG-HPD and Nx-PTHR-HPD groups, respectively; P < 0.05). In Nx rats on a HPD, the development of secondary hyperparathyroidism (286 +/- 19 pg/ml in the Nx-IPTG-HPD group) prevented a decrease in serum calcitriol levels (68 +/- 7 pg/ml). In contrast, serum calcitriol levels were low in the Nx-PTHR-HPD group (52 +/- 4 pg/ml, P < 0.05), which were deprived of the adaptative increase in endogenous PTH production. In conclusion, our results in rats indicate that in moderate renal failure, an elevated PTH level maintains calcitriol production and overcomes the inhibitory action of phosphorus retention.
影响因子：
15.9
作者：
PORTALE, AA;HALLORAN, BP;MORRIS, RC
通讯作者：
MORRIS, RC
在体外，膳食磷酸盐剥夺会增加大鼠肾脏中 1,25-二羟基维生素 D3 的合成。
DOI：
--
发表时间：
1983
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Gray,RW;Napoli,JL
通讯作者：
Napoli,JL
大鼠肾 25-羟基维生素 D3 1- 和 24- 羟化酶：它们的体内调节。
DOI：
10.1152/ajpendo.1984.246.2.e168
发表时间：
1984
期刊：
The American journal of physiology
影响因子：
--
作者：
Tanaka,Y;DeLuca,HF
通讯作者：
DeLuca,HF