办事指南

In brief : In the dark

点击量:   时间:2017-05-25 03:02:03

IF you get up in the middle of the night, better leave the light off. Researchers have learnt how even a short period of light shuts down the production of melatonin, a sleep-regulating hormone. The enzyme that makes melatonin in the pineal gland reaches a peak of activity in the middle of the night. By monitoring the enzyme in rats, David Klein and his colleagues at the National Institutes of Health in Bethesda, Maryland, found that even 15 minutes of light led to the enzyme’s destruction by a protein-chewing complex called a proteosome. Klein says in last week’s Science (vol 279,