During pregnancy, a group of cells in the pituitary gland called lactotrophs start to increase in size and number.

怀孕期间，垂体中的一组细胞“泌乳细胞”的体积和数量都会相应增加。

These lactotrophs secrete the hormone prolactin, and the increased levels of prolactin prepares the mammary glands to produce milk.

泌乳细胞分泌催乳素，而催乳素水平的增高使得乳腺可以产生乳汁。

So there is an increased blood demand without an increase in supply, making the lactotrophs hypoperfused.

因此，泌乳细胞的需求增加，但血供却未增加，造成泌乳细胞血供不足。

Even though there are more lactotrophs that are larger and more metabolically active, the blood supply to the pituitary gland remains the same.

即便泌乳细胞数量增多、体积增大、代谢也更活跃，但垂体的供血并未相应增加。

In other words, the lactotrophs are just barely getting enough oxygenated blood, and they will become ischemic and die if blood flow is reduced further.

换言之，泌乳细胞仅勉强获得足够的氧合血；如果血流量进一步减少，它们便会缺血乃至死亡。

Coupled with the increased demand for blood by the lactotrophs, the pituitary cells no longer receive enough oxygen to survive - resulting in ischemic necrosis.

加上泌乳细胞对血液的需求增加，垂体细胞因而无法得到充足的氧以维持生存，从而导致缺血性坏死。

All right, as a quick recap, in pregnancy the pituitary cells are getting just enough blood to survive because the lactotrophs increase in size and number, taking up more blood than usual.

好！快速回顾一下：在怀孕期间，脑垂体细胞仅能获得足够维持生存的血供，这是因为泌乳细胞的体积和数量都增加了，比平常需要摄入更多的血液。

Since there are more metabolically active lactotrophs around, they take up a larger proportion of the blood that supplies the pituitary gland, this increases the risk of ischemia in other cells of the pituitary as well.

由于泌乳细胞的新陈代谢相当活跃，它们占用了供应垂体的大部分血液，于是增加了垂体中其他细胞缺血的风险。

In Sheehan's syndrome, postpartum hemorrhage causes lactotrophs and other cells of the pituitary to die, resulting in low levels of prolactin, growth hormone, thyroid stimulating hormone, adrenocorticotropic hormone, luteinizing hormone, and follicle stimulating hormone.

在席汉综合征中，产后出血会导致泌乳细胞和垂体其他细胞的死亡，使得催乳素、生长激素、促甲状腺激素、促肾上腺皮质激素、黄体生成素和卵泡刺激素水平降低。