Musculotrophic effects of insulin receptors before and after denervation.
Insulin binding and metabolic effects have been used to assess properties of the insulin receptor of rodent skeletal muscles before and after denervation. It has been found that the amount of insulin-displaceable insulin binding on both type I (soleus) and type II (extensor digitorum longus) muscles rises slowly for up to 3 weeks after denervation, following a brief period of reduced binding. As estimated from weight loss and unstimulated deoxyglucose uptake, the extra binding sites are not functional. Stimulation in vitro with shocks or excess potassium can temporarily cause a relative increase in sugar uptake in both types of muscle, but an excess of insulin rapidly loses its effect in the soleus muscle. The effects of stimulation are taken to mean either conformational changes in the receptor or enhancement of some postbinding step, or both. It is suggested that the slow increase of binding sites for insulin after denervation may reflect loss of a neural substance normally effective in activating receptor degradation.
D000818:Animals; D004558:Electric Stimulation; D005947:Glucose / Q000378:metabolism; D007328:Insulin / Q000378:metabolism; D008297:Male; D051379:Mice; D008968:Molecular Conformation; D009121:Muscle Denervation; D009132:Muscles / Q000502:physiology*; D009928:Organ Specificity; D011188:Potassium / Q000494:pharmacology; D011972:Receptor, Insulin / Q000502:physiology*
D007328:Insulin; D011972:Receptor, Insulin; D005947:Glucose; D011188:Potassium