向男性避孕药更进一步(下)

The concentration of bicarbonate varies little from tissue to tissue with one notable exception.

碳酸氢盐的浓度在不同组织中变化不大，但有一个明显的例外。

In the epididymis, the tube in which mature sperm are stored, it is a fifth of the usual level.

在储存成熟精子的附睾管中，碳酸氢盐的浓度是通常水平的五分之一。

The significance of this is that, at ejaculation, a tiny pellet of sperm is pushed forward and mixed with seminal fluid, suddenly quintupling the bicarbonate concentration.

这种情况是因为，射精时一小团精子与精液混合，碳酸氢盐浓度瞬间提高五倍。

That causes sAC to produce a bunch of cAMP.

这导致sAC产生大量的cAMP。

This increase in cAMP then activates the sperm, and lets them start swimming and searching for an egg to fertilise.

cAMP的增加会激活精子活力，让它们开始移动并寻找卵子受精。

TDI-11861 blocks the places on sAC where bicarbonate would normally bind, rendering it unresponsive to this rapid change in concentration.

TDI-11861阻断了sAC上碳酸氢盐正常结合的点位，不让其对浓度的快速变化产生反应。

That stops them swimming.

这会阻止精子移动。

Although TDI-11861 inhibits sAC everywhere in the body, Dr. Buck and Dr. Levin say this is not a cause for concern.

尽管TDI-11861会抑制体内各处的sAC，但巴克博士和莱文博士表示，这没什么好担心的。

Some men lack functioning sAC because of a mutation.

一些男性因为基因突变而缺乏正常的sAC。

That results in infertility and a slightly raised incidence of kidney stones, but otherwise they are completely normal.

这会导致不孕不育和肾结石发病率略有上升，但除此之外是完全正常的。

So, while sAC appears to be a unique link in the chain of sperm mobilisation, the body has built plenty of redundancy into its means of generating cAMP.

因此，尽管sAC似乎是精子移动链中的一个独特环节，但人体在其生成cAMP的过程中制造了大量的冗余。

Whether Dr. Buck's and Dr. Levin's discovery will actually prove to be the long-sought breakthrough in the search for a Pill for men remains to be seen.

巴克博士和莱文博士的发现是否真的会成为科学家长期以来不断寻找的，在男性避孕药方面的突破，还有待观察。

More animal tests will be needed before trials on people can go ahead.

在进行人体试验之前，还需要进行更多的动物试验。

The two researchers are, however, already looking at other sAC-inhibiting compounds, to determine which performs best.

然而，这两位研究人员已经在寻找其它能够抑制sAC的化合物，以确定哪种化合物表现最好。

One approach they use is x-ray crystallography, which shows how molecules fit together at an atomic level.

他们使用的方法之一是x射线晶体学，它能够在原子水平上展示分子的排列方式。

With it, they have improved how well their compound binds to the right spot on sAC, and stays there - and they hope to do better still.

有了这项技术，巴克博士和莱文博士对化合物在sAC上的正确位置结合，并停留在那里的能力进行了改善——并且，他们希望做得更好。

Right now, men have less control over family planning than women do, and sometimes feel little responsibility for it.

目前，从计划生育的角度来说，男性付出的比女性少，并且时常认为他们不需要为此负责。

That is surely not unconnected with the fact that, according to the United Nations Population Fund, nearly half of pregnancies - 121m each year - are unplanned.

这也就造成了这样一个事实：根据联合国人口基金的数据，每年1.21亿次怀孕中，近一半是意外怀孕。

"This", Dr. Levin says, referring to sAC inhibition, "gives men the ability to be a partner."

“sAC抑制剂这一发现，”莱文博士说，“赋予了男性成为伴侣的能力。”

Who knows?

谁知道呢？

Some of them might even give it a try.

有些人甚至可能会试一试。