Scientists Discover Hormone that Regulates Sleep Also Activates Cancer Stimulating Protein

According to a Newswise.com press release, Southwestern Medical University has discovered that a hormone called orexin, which has been known to exert some control over sleep, hunger and metabolism also has a previously unknown function. It activates the protein HIF-1, which is a protein that has been known for some time to be related to cancerous tumor growth.

Researchers were studying the effects that orexin had on sleep, hunger and metabolism when they found that orexin stimulated the HIF-1 protein and that the protein also had a function in regulating healthy body tissues and functions. The research was published on-line in the November 14 journal Genes and Development. Dr. Thomas Kodadek, chief of translational research at UT Southwestern is the senior author of the study. Dr. Kodadek states, " HIF-1 is very big in the cancer community, so we were intrigued to find this important and very basic mechanism that is unrelated to cancer".

One of the previously known diseases associated with lack of orexin is narcolepsy. According to answers.com, "Narcolepsy is a disorder marked by excessive daytime sleepiness, uncontrollable sleep attacks, and cataplexy (a sudden loss of muscle tone, usually lasting up to half an hour)".

The research focused on orexin's effect on genes and whether it activated or de-activated them. One of the most unexpected results was the discovery that an element of HIF-1, called the HIF1-alpha was one of the most affected genes. Orexin's effect on the HIF1-alpha gene made the HIF1-alpha gene stimulate other genes that control metabolism. This research will help scientists to find out how metabolism works in the body. Orexin has been known to increase in the body when a person's blood sugar level drops . According to the press release, "the researchers hypothesized that when a body has low blood sugar and gets hungry, the increase in orexin activates HIF-1 production, revving up metabolism so the body gets the most energy out of the sugar on hand".

Orexin is important to the action of the HIF-1 protein in that it's effect on HIF-1 requires the protein to use oxygen to burn sugar. The HIF-1 protein in cancerous tumors does not require oxygen in order to burn sugar. Using oxygen to burn sugar is of greater benefit to the body because the sugar is burned rapidly and with un-necessary effort. Kodadek states, "Even though blood sugar levels are low, you're not only awake, but you're also energetic because of the action of HIF-1".

The study is important for several reason. First is the connection it revealed between orexin and HIF. Secondly, the study un-covered the previously un-known function of HIF-1, especially in relation to sleep. Perhaps, most importantly, the study makes known that there may be problems with anti-cancer treatments that are focused on HIF-1. Chemotherapy that is detrimental to HIF-1 could also have negative implications on the positive functions of HIF-1 in the body, according to Dr. Kodadek.

Sources Used:

www.newswise.com/articles/view/535374/?sc=dwtr
Hormone Links Sleep, Hunger and Metabolism

www.answers.com/narcolepsy?cat=health

http://www.utsouthwestern.edu/findfac/professional/0,2356,32680,00.html