Science Update - testosterone

Mandy - Now we're going to take our weekly trip over the ocean for a Science Update from Chelsea Wald and Bob Hirshon. This week they're going to be looking at the king of all hormones, testosterone, including its potential use in stopping the progression of MS and how too much of it may lead some birds to an early grave.

Chelsea - This week for the Naked Scientists we'll be talking about testosterone. Although it's present in both sexes, testosterone is commonly known as the male hormone. That's because males have more of it and it strongly influences male sex traits and mating habits. Now a study in birds shows that extra testosterone can give males a leg up in the mating game at a big price.

Bob - Would you die younger for a better sex life? Well that's what extra testosterone does for birds called dark - eyed juncos. North Dakota State University biologist Wendy Reed and her colleagues found that when young male juncos were treated with extra testosterone, they attracted older more fertile females, had more extra-marital sex and fathered more offspring than untreated males. But Reed says that attracting more mates also seemed to attract more predators.

Wendy - They also have a lower immune function than control males. And so they paid a cost that actually lowered survival rates.

Bob - What's more, their offspring were smaller and weaker than normal and the testosterone-treated dads tended to skip out on their parenting duties. Reed says that factors like these may keep junco populations natural testosterone levels in check.

Chelsea - And testosterone levels not only gives human males hairy chests, deep voices and an insatiable appetite for… sports, it may also protect them from multiple sclerosis. Men get the auto-immune disease less than women and when they do, it's often when their testosterone levels have dropped with age. So a team from the University of California Los Angeles had ten men with MS rub a testosterone gel on their skin every day for a year. The team then tested their brain processing speed and memory. Neurologist Nancy Sicotte says the result was an improvement on all counts.

Nancy - And in general in people in MS we would have expected to see a decline in those abilities because that's typically what happens. So it suggests that not only could they not get worse but they might actually have some improvements.

Chelsea - If they can confirm this effect in larger studies, this treatment could be the first to protect MS patients from brain damage. It wouldn't be suitable for women because of the side effects but the same team has found that the pregnancy hormone esterol could work for women.

Bob - Thanks Chelsea. Well you've heard of cyber gambling and cyber sex: next week we'll be talking about a new project that will let anyone with an internet connection dissect fish.

Chelsea - Until then, I'm Chelsea Wald.

Bob - And I'm Bob Hirshon for AAAS, The Science Society. Back to you Naked Scientists.