Can steroids save your life

類固醇可以挽救你的生命嗎？

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

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

and shots to ease inflammation.

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

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

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

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

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

rather than shared effects on the body.

類固醇：這類物質(zhì)在體育賽事中的 使用早已臭名昭著。

但它們也常見于吸入器， 治療藤毒和濕疹的藥膏，

以及緩解炎癥的注射液中。

這些藥物中的類固醇 和用于促進肌肉生長的類固醇不同。

實際上，它們都是基于 另一種類固醇物質(zhì)——

我們?nèi)梭w可以自然合成， 且維持生命所必需的類固醇。

退一步說， 類固醇種類繁多的原因是

類固醇這一專有名詞 泛指具有共同分子結(jié)構(gòu)，

而非對人體造成相同影響的物質(zhì)。

Steroids can be naturally occurring ?or synthetic,

but what all steroids have in common ?is a molecular structure

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

arranged in three hexagons ?and one pentagon.

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

though most also have side chains—

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

類固醇可以天然存在 或是通過人工合成，

但所有類固醇物質(zhì)的共同特性 是它們的分子結(jié)構(gòu)。

這種分子結(jié)構(gòu)由 4?個環(huán) （共 17?個碳原子）組成：

3?個六碳環(huán)和 1?個五碳環(huán)。

一個分子必須具有這樣精確的排列 才能被稱作為固醇類物質(zhì)，

盡管大多數(shù)分子也含有側(cè)鏈——

這些額外的原子 可以極大改變分子的功能。

Steroids get their name ?from the fatty molecule cholesterol.

In fact, our bodies make steroids ?out of cholesterol.

That fatty cholesterol base ?means that steroids

are able to cross fatty cell membranes ?and enter cells.

Within the cell, they can directly ?influence gene expression

and protein synthesis.

This is different from many other types ?of signaling molecules,

which can’t cross the cell membrane

and have to create their effects ?from outside the cell,

through more complicated pathways.

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

類固醇的命名 源于脂肪分子膽固醇。

實際上，我們?nèi)梭w 會從膽固醇中生成類固醇。

脂肪膽固醇基底能夠 讓類固醇物質(zhì)

穿過脂肪細胞膜并進入細胞。

在細胞內(nèi)， 它們可以直接影響基因表達

和蛋白合成。

這和許多其它的信號分子不同，

因為后者無法穿過細胞膜，

只能通過更加復雜的方式

在細胞外產(chǎn)生作用。

所以相比其它分子， 類固醇可以更快的產(chǎn)生作用。

Back to the steroids ?in anti-inflammatory medications:

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

Cortisol is the body’s ?primary stress signal,

and it has a huge range of functions.

When we experience a stressor—

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

to an infection or low blood sugar—

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

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

The adrenal glands produce cortisol, ?and release some constantly.

說回消炎藥中的類固醇：

這類類固醇都是基于一種 天然存在的類固醇，即皮質(zhì)醇。

皮質(zhì)醇是人體的主要壓力信號，

并且具有很多功能。

每當我們經(jīng)歷一種應激源——

比如和朋友的一場爭執(zhí)， 突然發(fā)現(xiàn)一頭熊，

感染或低血糖——

大腦就會通過下丘腦向腦垂體 發(fā)出信號來做出反應，

隨后，腦垂體向腎上腺發(fā)送信號，

最終腎上腺產(chǎn)生皮質(zhì)醇， 并不斷進行釋放。

But when they receive the signal ?from the pituitary gland,

they release a burst of cortisol,

which spurs the body to generate ?more glucose for energy,

decrease functions not immediately ?related to survival, like digestion,

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

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

like insomnia and lowered mood ?if they last too long.

但是當腎上腺?從腦垂體接收到信號時，

它們所釋放的大量皮質(zhì)醇

會刺激人體產(chǎn)生?更多的葡萄糖作為能量來源，

降低與生存沒有直接關(guān)系的?功能運作，比如消化，

并且能激活人體的?“戰(zhàn)斗、逃跑或原地不動”反應機制。

這在短期內(nèi)很有幫助，?但如果持續(xù)時間太長，

將可能導致一些副作用，?諸如失眠癥和情緒低落。

Cortisol also interacts ?with the immune system in complex ways—

depending on the situation,

it can increase or decrease ?certain immune functions.

In the process of fighting infection,

the immune system ?often creates inflammation.

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

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

皮質(zhì)醇同樣也和免疫系統(tǒng) 有著復雜的相互作用——

根據(jù)實際情況，

皮質(zhì)醇可以加強或降低 一定的免疫功能。

在人體抵抗感染的過程中，

免疫系統(tǒng)通常會產(chǎn)生炎癥。

皮質(zhì)醇能夠抑制 免疫系統(tǒng)產(chǎn)生炎癥的能力，

但同樣僅在短期內(nèi)有效。

But too much cortisol ?can have negative impacts,

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

To prevent levels ?from staying high for too long,

cortisol suppresses the signal ?that causes the adrenal glands

to release more cortisol.

Medicinal corticosteroids channel ?cortisol’s effects on the immune system

to fight allergic reactions, ?rashes, and asthma.

All these things are forms ?of inflammation.

過多的皮質(zhì)醇對人體 具有負面影響，

例如降低免疫系統(tǒng) 再生骨髓和淋巴結(jié)的能力。

為了防止皮質(zhì)醇的含量 長時間處于過高水平，

皮質(zhì)醇會抑制

引起腎上腺釋放 更多皮質(zhì)醇的信號。

藥用皮質(zhì)類固醇可通過引導 皮質(zhì)醇對免疫系用的作用

來對抗過敏反應、 皮疹和哮喘。

所有這些都是 炎癥的不同表現(xiàn)形式。

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

they enhance the body’s cortisol supply,

which in turn shuts down ?the hyperactive immune responses

that cause inflammation.

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

by suppressing gene expression ?of inflammatory signals.

很多合成類固醇 也有著相同的基礎作用機理：

它們促進人體的皮質(zhì)醇供應，

進而阻止了引發(fā)炎癥的

過度免疫反應。

這些皮質(zhì)類固醇潛入細胞中， 通過抑制炎癥信號的基因表達

來關(guān)閉細胞的“警報”。

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

the skin, or the lungs.

Intravenous or oral versions, used ?to treat chronic autoimmune conditions

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

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

a process analogous to a constant ?asthma attack or rash.

A constant low dose of steroids

can help keep this renegade immune response under control—

but because of the negative psychological ?and physiological effects

of longterm exposure,

higher doses are reserved ?for emergencies and flare-ups.

吸入器和藥膏中的類固醇 僅影響著一個器官——

皮膚或是肺部。

常用于治療慢性自身免疫性疾病 （例如狼瘡或炎癥性腸?。┑?/p>

靜脈注射或口服形式的類固醇 則能對全身造成影響。

在患有此類疾病的情況下， 人體免疫系統(tǒng)會攻擊自身細胞，

這是一個類似于哮喘頻繁發(fā)作 或皮疹不斷復發(fā)的過程。

恒定低劑量的類固醇

能有助于控制 上述叛逆的免疫反應——

但對于因長期暴露于 高劑量所產(chǎn)生的

負面身心影響，

較高劑量的類固醇通常 只被用于應對緊急和突發(fā)事件。

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

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

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

And while corticosteroids ?won’t give you giant muscles,

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

盡管哮喘發(fā)作、藤毒紅腫， 以及腸易激綜合癥

可能看似毫不相關(guān)， 但它們實際有著共性：

都是一種弊大于利的免疫反應。

雖然皮質(zhì)類固醇 無法賜予你健碩的肌肉，

但它們卻是人體 抵抗自身傷害的最佳防御工具。