January Article 3

Article/Link: Exercise Hormone May Fight Obesity and Diabetes by Gretchen Reynolds; published: January 11, 2012; accessed: January 13, 2012

Article Summary:

According to new studies, a hormone released during exercise may be responsible for changing the type of fat in the body to fat that burns calories. They studied the effect of exercise on people and rats, and realized that exercise released a protein that breaks into various pieces, including a newly discovered hormone called irisin. This hormone enters the bloodstream and through a series of biological processes, turns fat that is inactive into fat that burns calories. This study underscores the importance of exercise in maintaining a healthy weight and a healthy body. The scientists also suggest this hormone may help prevent diabetes, because of the results of the experiments with mice they performed. In addition, they noted that the hormone was exactly the same in humans as in rats, which may be a clue as to the importance of this hormone across the animal kingdom, because in both species, the hormone has evolved to the same shape.
Vocabulary:

Word 1: Preternatural

A. Mice bred to produce preternaturally large amounts of PGC1a in their muscles are typically resistant to age-related obesity and diabetes, much as people who regularly exercise are.

B. Preternatural: “out of the ordinary course of nature; exceptional or abnormal,” first used in 1530 and derived from Latin phrase praeter naturam meaning “beyond nature” (dictionary.reference.com)

C. Mussooire very rarely receives a preternatural amount of rain during the monsoon season.

Word 2: Visceral

A. It apparently enters the bloodstream and surfs to fat cells, where, by providing various biochemical signals or messages, it begins turning regular fat — especially deep, visceral fat clustered around organs — into brown fat.

B. Visceral: pertaining to the “organs in the cavities of the body, especially those in the abdominal cavity,” first used in 1645 and from Latin viscera, meaning “internal organs”
(dictionary.reference.com)

C. Everyone at Woodstock has visceral fat; it is an exceptionally vital fat for organ protection.


Word 3: Adipocyte

A. If that last statement didn’t make your eyebrows rise in surprise, you are not an adipocyte biologist.

B. Adipocyte: “fat cell” (dictionary.reference.com)

C. It would be interesting for Woodstock A.P. Biology students to study adipocytes.


Response:
Overall, I thought this was a very interesting article, but I think some of the assumptions the scientists made in the studies are misleading. First of all, I found the title of the article, Exercise Hormone May Fight Obesity and Diabetes, to be misleading. This implies that the hormone discussed in the article (irisin) may help fight diabetes in people. Dr. Spiegelman, one of the study leaders, says that in "additional experiments with mice fattened on high-fat kibble, injections of the Fndc5 protein, which cleaves into irisin, improved the animals’ glucose tolerance." This simply means the mice did not develop diabetes when injected with the Fndc5 protein. However, the article fails to address numerous questions about thatstatement. The article does not mention what the effect on the increase of irisin in people has on their susceptibility to diabetes. The article does not mention that perhaps other byproducts of the Fndc5 protein could have lead to the improved glucose tolerance. The article jumps to the conclusion that just because the injection of the Fndc5 protein into mice increased their resistance to diabetes, the same would be true for humans. When someone reads the title of this article without investigating the entire article and examining it, they could be easily mislead, which I don't think is right.