Bright Light Exposure Increases Male Hormone

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Bright Light Exposure Increases Male HormoneLibraries

Medical News

Description

Researchers at the University of California, San Diego School of Medicine have

found that the levels of a pituitary hormone that increases testosterone are

enhanced after exposure to bright light in the early morning. The findings

suggest that light exposure might serve some of the same functions for which

people take testosterone and other androgens.

 

 

 

Researchers at the University of California, San Diego (UCSD) School of Medicine

have found that the levels of a pituitary hormone that increases testosterone

are enhanced after exposure to bright light in the early morning. The findings

suggest that light exposure might serve some of the same functions for which

people take testosterone and other androgens.

 

One of the study's authors, Daniel Kripke, M.D. UCSD professor of psychiatry,

added " the study also supports data that bright light can trigger ovulation in

women, which is also controlled by luteinizing hormone (LH), the pituitary

hormone we studied. "

 

Published in the current issue of the journal Neuroscience Letters (341, 2003,

25-28), the study looked at LH excretion following bright light exposure (1,000

lux) from 5-6 a.m. each morning for five days in 11 healthy men ages 19-30. The

same group of men had their LH measured again after exposure to a placebo light

(less than 10 lux) from 5-6 a.m. for five days.

 

The researchers found that LH levels were increased 69.5 percent after bright

light exposure in the early morning.

 

The researchers also measured levels of melatonin, a hormone whose secretion is

elevated in darkness at night, and inhibited by light. Previous studies in

animals had indicated that melatonin secretion might inhibit the effects of

light on LH. However, the UCSD team did not find such evidence in humans.

 

" This finding suggests that in humans, the duration of melatonin secretion may

be less important in mediating light effects on LH secretion, " said Shawn

Youngstedt, Ph.D., UCSD assistant project scientist and one of the paper's

authors.

 

Previous studies by the Kripke group and others have shown that bright light

exposure helps alleviate the symptoms of depression. According to the study's

authors, sexual dysfunction such as loss of libido and decreased sexual

activity, which are known depressive symptoms as well as side effects of newly

developed antidepressants, may be helped by bright light exposure.

 

" The effects of bright light exposure on the LH secretion of normal volunteers

should be replicated in depressed patients to elucidate the therapeutic effect

of light exposure on the decreased LH levels and sexual dysfunctions of

depression, " the authors stated in the paper.

 

The paper's first author was In-Young Yoon, M.D., Ph.D., formerly a visiting

scholar at UCSD and currently an assistant professor, Seoul National University

School of Medicine, Korea. Jeffrey A. Elliott, Ph.D., UCSD associate research

scientist was also an author on the paper. The study was supported by the

National Institutes of Health.

 

 

 

 

© 2003 Newswise. .

 

 

 

 

 

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