Daily release of hormones depends on the coordinated activity of clocks in two parts of the brain, a finding that could have implications for human diseases.

Here’s how it’s supposed to work: Your brain sends signals to your body to release different hormones at certain times of the day. For example, you get a boost of the hormone cortisol — nature’s built-in alarm system — right before you usually wake up.

But hormone release actually relies on the interconnected activity of clocks in more than one part of the brain. New research from Washington University in St. Louis shows how daily release of glucocorticoids depends on coordinated clock-gene and neuronal activity rhythms in neurons found in two parts of the hypothalamus, the suprachiasmatic nucleus (SCN) and paraventricular nucleus (PVN).

The new study, conducted with freely behaving mice, is published Oct. 1 in Nature Communications.

«Normal behavior and physiology depends on a near 24-hour circadian release of various hormones,» said Jeff Jones, who led the study as a postdoctoral research scholar in biology in Arts & Sciences and recently started work as an assistant professor of biology at Texas A&M University. «When hormone release is disrupted, it can lead to numerous pathologies, including affective disorders like anxiety and depression and metabolic disorders like diabetes and obesity.

«We wanted to understand how signals from the central biological clock — a tiny brain area called the SCN — are decoded by the rest of the brain to generate these diverse circadian rhythms in hormone release,» said Jones, who worked with Erik Herzog, the Viktor Hamburger Distinguished Professor in Arts & Sciences at Washington University and senior author of the new study.

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Materials provided by Washington University in St. Louis. Original written by Talia Ogliore. Note: Content may be edited for style and length.