Bone remodelling as a whole is highly dependent on serum calcium levels, which, in turn, are kept in the normal range by a balance between parathyroid hormone, or PTH, calcitonin and vitamin D.

整个骨重建进程高度依赖于血清钙的含量，而将血清钙的含量持在正常值范围内是由甲状旁腺激、降血钙与D间的制约平衡所控制的。

Now, that calcium's still in the lumen, but parathyroid hormone also affects the distal convoluted tubule and increases calcium reabsorption.

这时，钙仍然在腔内，但甲状旁腺激也会影响远曲小管，增加对钙的再吸收。

Related to this is pseudohyporparathyroidism, which is where the kidneys simply don't respond to parathyroid hormone because of a genetic defect in the parathyroid hormone receptor.

与此相关的是伪甲状旁腺功能减退症，也就是由于甲状旁腺激受体的基缺陷，肾脏不对甲状旁腺激作出反应。

Additionally, parathyroid hormone can boost 1-alpha-hydroxylase activity, which forms more active vitamin D, increasing gut absorption of calcium.

此外，甲状旁腺激可以增加1-α-羟化酶的活性，从而形成更多有活性的D，增加肠道对钙的吸收。

So when the dust settles, as a result of parathyroid hormone, phosphate is lost in the urine while ionized calcium is kept in the blood, so ionized calcium levels rise and phosphate levels fall!

所以最终导致的结果是磷酸盐在尿液，而游离钙被保存在血液，此游离钙含量上升，而磷酸盐含量下降！

Now, the levels of calcium and phosphate in the bone, but also in the blood, are regulated by vitamin D and parathyroid hormone, or PTH.

钙和磷不仅存在于骨，也存在于血液，钙磷含量的调节受D和甲状旁腺激（PTH）调控。

If osteoporosis is really advanced, teriparatide, a recombinant parathyroid hormone can be used.

如果骨质疏松十分严重，可以使用特立帕肽这种重组甲状旁腺激治疗。

This affects the amount of parathyroid hormone that gets released by the parathyroid gland.

这从而会影响甲状旁腺释放甲状旁腺激的量。

Ok, now let's have a quick look at parathyroid hormone.

好，来看甲状旁腺的功能。

Less calcium entering the blood is the most common cause and can be due to hypoparathyroidism, or lower levels or lower activity of parathyroid hormone.

钙离子进入血液的量减少是最常见的原，可能是由于甲状旁腺功能减退或者甲状旁腺激的量或者活性降低。

The parathyroid hormone gets the bones to release calcium, and gets the kidneys to reabsorb more calcium so it's not lost in the urine as well as synthesize calcitriol also known as 1,25-dihydroxycholecalciferol also known as active vitamin D.

甲状旁腺激作用于骨骼使其释放钙离子，也作用于肾脏而增加钙的重吸收，这样钙就不会随尿液排出；以及用于合成骨化三醇，也称为1，25-二羟基胆钙化固醇，又叫活性D。

Lastly, parathyroid hormone increases calcium reabsorption and reduces the reabsorption of phosphate from the kidneys, so more phosphate is excreted through the urine.

最后，甲状旁腺激可以促进肾脏对钙的重吸收，而减少对磷酸盐的重吸收，此导致尿磷升高。

Now, even though parathyroid hormone stimulates bone resorption, it's been found that intermittent injections with teriparatide activates osteoblasts more than osteoclasts, therefore increasing bone formation.

其实，即使甲状旁腺激刺激骨吸收，研究发现间歇性注射特立帕肽激活了更多造骨细胞而非破骨细胞，从而增强骨长。

As calcium levels in the blood fall, parathyroid hormone is released, causing the bones to lose calcium.

随着血钙降低，甲状旁腺激释放，导致溶骨作用。

Since parathyroid hormone tells the kidneys to save calcium and get rid of phosphate, calcium again gets lost and phosphate builds up in the blood, following the same pattern as kidney disease, including the thinning of the bones.

为甲状旁腺激可以促使肾脏储存钙和去除磷酸盐，钙再次流而磷酸盐在血液累积，这和肾病的机理一致，包括骨质变薄。

All right, so since, again, parathyroid hormone causes excretion of phosphate and reabsorption of calcium, then another cause of hyperphosphatemia is hypoparathyroidism, when the parathyroid glands don't produce enough parathyroid hormone in the first place.

为甲状旁腺激会导致磷酸盐的排泄以及钙的再吸收，那引发高磷血症的另一原就是甲状旁腺功能减退，也就是当甲状旁腺首先不能产足够的甲状旁腺激时。

It turns out, though, that parathyroid hormone also shuts this down.

不过，事实证明甲状旁腺激也会阻止这种反应。

To identify the cause, lab tests are typically done, which includes tests for parathyroid hormone, vitamin D, albumin, phosphorus, and magnesium.

为了确定病，通常要做实验室检查，其包括甲状旁腺激、D、白蛋白、磷和镁的检测。

We have teriparatide, which is a parathyroid hormone analogue that also reduces fracture risk and increases bone mineral density in patients with osteoporosis.

我们还有特立帕肽，这是一种甲状旁腺激类似物，能够降低骨质疏松症患者的骨折风险，并增加骨密度。

If calcium levels fall, the four parathyroid glands buried within the thyroid gland release parathyroid hormone which frees up both calcium and phosphate ions from the bones.

如果钙水平下降，那么在甲状腺内的四个甲状旁腺释放甲状旁腺激，导致骨骼释放钙和磷酸盐离子。