DALLAS, Jul 1, 2008 (UPI via COMTEX) -- A U.S. study has linked growth hormone
to starvation in what scientists say might be a clue to increasing life span and
developing diabetes treatments.
University of Texas Southwestern Medical Center researchers used genetically
altered mice in the study that found the actions of growth hormone are blocked
during fasting by a fat-burning hormone called FGF21.
Growth hormone has many functions, the scientists said, such as controlling the
length of developing arm and leg bones in children. But it also, among other
things, increases levels of IGF-1, a hormone that promotes growth. Too much
growth hormone can cause insulin resistance, resulting in diabetes.
In the study, mice genetically altered to produce excess FGF21 grew to be much
smaller than ordinary mice, although they ate more and had more fat in
proportion to their size. Paradoxically, the altered, smaller mice produced much
greater amounts of growth hormone than normal.
"In addition, intermittent fasting -- which increases FGF21 concentrations --
also extends life span in mice," said Professor Steven Kliewer, senior author of
the study. "This raises the intriguing possibility that FGF21 might be a
longevity factor."
The study is reported in the journal Cell Metabolism.
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Copyright 2008 by United Press International