Can steroids save your life? - Anees Bahji

譯者: Lilian Chiu 審譯者: Chengyu Li

Steroids: they’re infamous for their use in sports.

類固醇：因運動員在比賽中使用 導致它聲名狼藉。

But they’re also found in inhalers, creams to treat poison ivy and eczema,

但它也存在於吸入器、

治療毒長春籐及濕疹的乳膏，

and shots to ease inflammation.

以及減輕發炎的注射藥物中。

The steroids in these medicines aren’t the same as the ones used to build muscle.

在這些藥物中的類固醇和用來 塑造肌肉所用的類固醇並不相同。

In fact, they’re all based on yet another steroid—

事實上，它們都是 以另一種類固醇為基礎——

one our body produces naturally, and we can’t live without.

我們的身體自己分泌的類固醇， 沒有它我們無法生存。

Taking a step back, the reason there are so many different steroids

先退回來一步，之所以 有這麼多種類固醇的原因，

is because the term refers to substances with a shared molecular structure,

是因為這個詞其實指的是 具有某一種分子結構的物質，

rather than shared effects on the body.

而不是對身體的某些效果。

Steroids can be naturally occurring or synthetic,

類固醇有天然的和合成的，

but what all steroids have in common is a molecular structure

但各種類固醇的共同點 就是分子結構，

that consists of a base of four rings made of 17 carbon atoms

它們的基礎結構是由 十七個碳原子組成的四個環，

arranged in three hexagons and one pentagon.

排列成三個六角形和一個五角形。

A molecule must contain this exact arrangement to be a steroid,

有這種排列方式的分子， 才能被稱為是類固醇，

though most also have side chains—

不過大部分的類固醇 通常也有側鏈——

additional atoms that can dramatically impact the molecule’s function.

額外的原子能顯著影響分子的功能。

Steroids get their name from the fatty molecule cholesterol.

類固醇的名稱來自 脂肪膽固醇分子。

In fact, our bodies make steroids out of cholesterol.

事實上，我們的身體 利用膽固醇來製造類固醇。

That fatty cholesterol base means that steroids

以脂肪膽固醇為基礎， 意味著類固醇可以

are able to cross fatty cell membranes and enter cells.

通過脂質細胞膜，進入細胞中。

Within the cell, they can directly influence gene expression

在細胞中，它能夠直接影響到

基因表現以及蛋白質合成。

and protein synthesis.

This is different from many other types of signaling molecules,

這和許多其他類型的 傳訊分子有所不同，

which can’t cross the cell membrane

它們無法穿過細胞膜，

and have to create their effects from outside the cell,

因此必須用比較複雜的途徑，

through more complicated pathways.

在細胞外產生它們的效應。

So steroids can create their effects faster than those other molecules.

所以，類固醇產生效應的速度 比那些其他類型的分子更快。

Back to the steroids in anti-inflammatory medications:

回到抗炎藥物中的類固醇：

all of these are based on a naturally occurring steroid called cortisol.

它們都是以一種天然類固醇 為基礎：皮質醇（可體松）。

Cortisol is the body’s primary stress signal,

皮質醇是身體的主要壓力訊號，

and it has a huge range of functions.

它的功能相當多樣。

When we experience a stressor—

當我們碰到壓力源時——

anything from a fight with a friend, to spotting a bear,

從和朋友爭吵，到看到熊，

to an infection or low blood sugar—

到感染或低血糖都算——

the brain reacts by sending a signal from the hypothalamus to the pituitary gland.

大腦的反應就是從丘腦下部

向垂體發出訊號。

The pituitary gland then sends a signal to the adrenal glands.

接著，垂體會向腎上腺發出訊號。

The adrenal glands produce cortisol, and release some constantly.

腎上腺平時就會產生皮質醇， 並不斷分泌少量皮質醇。

But when they receive the signal from the pituitary gland,

但，當腎上腺接收到 來自垂體的訊號時，

they release a burst of cortisol,

就會大量釋放皮質醇，

which spurs the body to generate more glucose for energy,

刺激身體，讓身體產生 更多葡萄糖以提供能量，

decrease functions not immediately related to survival, like digestion,

減低不會立即影響 生命的功能（如消化），

and can activate a fight-flight-or-freeze response.

並啟動「戰鬥、逃跑或定格反應」。

This is helpful in the short term, but can cause undesirable side effects

短期而言這是有用的， 但若持續太久，

會造成不好的副作用， 比如失眠和心情低落。

like insomnia and lowered mood if they last too long.

Cortisol also interacts with the immune system in complex ways—

皮質醇也會和免疫系統 產生複雜的交互作用——

depending on the situation,

依情況而異，皮質醇有可能會 增強或降低某些免疫功能。

it can increase or decrease certain immune functions.

In the process of fighting infection,

在對抗感染的過程中，

the immune system often creates inflammation.

免疫系統也常會引起發炎。

Cortisol suppresses the immune system’s ability to produce inflammation,

皮質醇會抑制免疫系統 引起發炎的能力，

which, again, can be useful in the short term.

同樣的，短期來說是有用的。

But too much cortisol can have negative impacts,

但若皮質醇太多， 會帶來負面的影響，

like reducing the immune system’s ability to regenerate bone marrow and lymph nodes.

比如降低免疫系統再生 骨髓和淋巴結的能力。

To prevent levels from staying high for too long,

為了避免皮質醇太長時間 一直處在過高的濃度，

cortisol suppresses the signal that causes the adrenal glands

皮質醇會產生抑制促使腎上腺分泌

to release more cortisol.

釋放更多皮質醇的訊號。

Medicinal corticosteroids channel cortisol’s effects on the immune system

藥用皮質類固醇會把 皮質醇對免疫系統的效應

to fight allergic reactions, rashes, and asthma.

拿來對抗過敏反應、 疹子，和氣喘。

All these things are forms of inflammation.

上述這些都是不同形式的發炎。

There are many synthetic steroids that share the same basic mechanism:

有許多種合成類固醇 也有同樣的基本機制：

they enhance the body’s cortisol supply,

它們能提高體內的皮質醇濃度，

which in turn shuts down the hyperactive immune responses

從而停止造成發炎的 過度免疫反應。

that cause inflammation.

These corticosteroids sneak into cells and can turn off the “fire alarm”

這些皮質類固醇會溜入細胞中，

透過抑制發炎訊號的基因表現，

by suppressing gene expression of inflammatory signals.

將「火警警報」關閉。

The steroids in inhalers and creams impact only the affected organ—

在吸入器和乳膏中的類固醇 只會影響到它們接觸的器官——

the skin, or the lungs.

皮膚或肺部。

Intravenous or oral versions, used to treat chronic autoimmune conditions

靜脈注射或口服的類固醇 可用來治療慢性自體免疫病症，

like lupus or inflammatory bowel disease, impact the whole body.

如狼瘡或發炎性腸道疾病， 這些類固醇就會影響到全身。

With these conditions, the body’s immune system attacks its own cells,

得了這類病症，身體的免疫系統 會攻擊其自身的細胞，

a process analogous to a constant asthma attack or rash.

這個過程就如同 經常性的氣喘或疹子。

A constant low dose of steroids

持續使用低劑量的類固醇

can help keep this renegade immune response under control—

可以協助控制這種 叛逆的免疫反應——

but because of the negative psychological and physiological effects

但因為長時間接觸類固醇 會對身心有負面的影響，

of longterm exposure,

higher doses are reserved for emergencies and flare-ups.

更高的劑量只會用在 緊急和突發情況。

While an asthma attack, poison ivy welts, and irritable bowel syndrome

雖然氣喘發作、毒長春藤條狀疹，

及大腸激躁症似乎完全沒有關聯，

might seem totally unrelated, they all have something in common:

但它們都有一個共通點：

an immune response that’s doing more harm than good.

弊多於利的免疫反應。

And while corticosteroids won’t give you giant muscles,

雖然皮質類固醇 不會讓你長出巨肌，

they can be the body’s best defense against itself.

它們卻可能成為身體 對抗自己的最佳防禦武器。