It blocks a protein called endothelin, which is secreted by prostate tumors in large amounts and helps them metastasize.

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Growth hormone is a naturally occurring substance secreted by the brain that helps guide growth in childhood and maintain muscle mass during adulthood.

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Dr Vollrath's examination of Crassicorophium showed that the material is secreted by glands similar to those used by barnacles to make their cement.

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No one is exactly sure why HCG is secreted by choriocarcinoma tumors, but what is certain is that having this form of testicular cancer is extremely bad.

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That's why, for instance, researchers can make accurate predictions about our eating habits, academic interests and political beliefs based on the trail of data secreted by our smartphones.

WSJ: Our Social Networks, Ourselves

Once their stomachs are tiny, most patients not only eat far less but also lose the desire to over-eat, possibly because of changes in a hormone called ghrelin that is secreted by the stomach.

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Hunting an animal may be tiresome but necessary, so endorphins are secreted during exertion to numb the discomfort induced by lactic acid production in the muscles.

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Secreted proteins, which include growth hormone, insulin and EPO (erythropoietin), are used by the body as molecular messengers to pass signals from one part of the body to another.

FORBES: Companies & Strategies

From a French fur trader with an iron hand to the Army Corps of Engineers reshaping the riverbed, Indian casinos built on brownfields to 280, 000 radioactive mice buried at the Falls, many of Niagara's stories are like the drums secreted in its landfills: shoved out of sight, covered over to look presentable, and driven by with glazed eyes, a quick flick of the radio volume.

NPR: Excerpt: 'Inventing Niagara'