Growth hormone-releasing hormone depletion in the female rat: similarities to aging.
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.
Department of Orthopaedic Surgery, University of Nebraska Medical Center, Omaha, USA.
M C
MC
Thompson
N S
NS
Norton
J F
JF
Rodriguez-Sierra
L
L
Lippiello
D000375:Aging / Q000502:physiology*; D000818:Animals; D015519:Bone Density; D005260:Female; D013006:Growth Hormone / Q000032:analysis; D013007:Growth Hormone-Releasing Hormone / Q000172:deficiency*; D007031:Hypothalamus / Q000737:chemistry; D010902:Pituitary Gland / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D012970:Sodium Glutamate / Q000494:pharmacology
D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone; D012970:Sodium Glutamate