Journals of Gerontology Series A: Biological Sciences and Medical Sciences, Vol 51, Issue 1 B83-B90, Copyright © 1996 by The Gerontological Society of America
Growth hormone-releasing hormone depletion in the female rat: similarities to aging
MC Thompson, NS Norton, JF Rodriguez-Sierra and L Lippiello
Department of Orthopaedic Surgery, University of Nebraska Medical Center, Omaha, USA.
The age-related decline in growth hormone (GH) secretion has been largely
attributed to age-related degeneration of hypothalamic growth
hormone-releasing hormone (GHRH)-producing neurons. GH decline has recently
been linked to age-related bone changes in humans. Bone loss and decreased
bone strength are common in aging rats and humans, but density of remaining
mineral tissue is known to be increased. The effect of induced hypothalamic
GHRH deficiency on bone was assessed, and similarities between bone changes
encountered and those taking place in aging were identified. Female rats
received monosodium glutamate (MSG) following birth, and they were
euthanized at 19 weeks of age. Femurs from MSG-treated rats had greater
mineral density (p < .05), greater mineral/matrix ratio (p < .01),
lower mineral apposition rate (p < .005), and lower bone formation rate
(p < .05). These results suggest that hypothalamic GHRH decline plays a
substantial role in the development of bone pathology similar to that
observed in aging individuals.
