Glycosaminoglycan-promoted muscle reinnervation and insulin-like growth factor-I levels are affected by anti-growth hormone-releasing hormone exposure.
The present study shows that exposure to antibodies to growth hormone-releasing hormone (GHRH) partially counteracted the promoting effects of treatment with glycosaminoglycans (GAGs) on muscle reinnervation. Sciatic nerve crush was performed in 2-day-old rats, and reinnervation of the extensor digitorum longus muscle was monitored. The extent of reinnervation was rather poor in saline-treated rats, whereas in GAG-treated rats the extent of muscle reinnervation, the recovery of nerve-evoked muscle twitch tension, and the number of motor neurons reinnervating the extensor digitorum longus muscle were greatly enhanced. In addition, treatment with glycosaminoglycans increased markedly insulin-like growth factor-I (IGF-I) levels in denervated muscles. Both types of stimulatory action exerted by GAGs were affected by concomitant exposure to anti-GHRH, with abolition of IGF-I muscle increase and a smaller enhancement in muscle reinnervation.
Gorio
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A
Pharmacological Laboratories, Department of Medicine, Surgery, and Odontoiatry, Polo H. San Paolo, Via A. Di Rudini 8, 20142 Milan, Italy. alfredo.gorio@unimi.it
Citterio
C
C
Muller
E E
EE
Di Giulio
A M
AM
D000818:Animals; D000831:Animals, Newborn; D000906:Antibodies / Q000494:pharmacology*; D001284:Atrophy / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D002452:Cell Count; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002772:Cholera Toxin; D003714:Denervation; D007839:Functional Laterality / Q000187:drug effects / Q000502:physiology; D006025:Glycosaminoglycans / Q000494:pharmacology*; D020439:Growth Cones / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D013007:Growth Hormone-Releasing Hormone / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006614:Hindlimb / Q000187:drug effects / Q000294:innervation / Q000378:metabolism; D006735:Horseradish Peroxidase; D007334:Insulin-Like Growth Factor I / Q000187:drug effects / Q000378:metabolism*; D009046:Motor Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D018482:Muscle, Skeletal / Q000187:drug effects / Q000294:innervation* / Q000378:metabolism; D009416:Nerve Regeneration / Q000187:drug effects* / Q000502:physiology; D009929:Organ Size / Q000187:drug effects / Q000502:physiology; D010525:Peripheral Nerves / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020127:Recovery of Function / Q000187:drug effects / Q000502:physiology
D000906:Antibodies; D006025:Glycosaminoglycans; D007334:Insulin-Like Growth Factor I; D002772:Cholera Toxin; D013007:Growth Hormone-Releasing Hormone; D006735:Horseradish Peroxidase