GLUT-4 protein and citrate synthase activity in distally or proximally denervated rat soleus muscle

Donovan L. Fogt, Michael J. Slentz, Marc E Tischler, Erik J Henriksen

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5 Citations (Scopus)

Abstract

The potential role of neurotrophic factors in the decline of glucose transporter (GLUT-4) protein levels and citrate synthase (CS) activity was studied by comparing distally with proximally denervated juvenile rat soleus muscle. Severing of the tibial nerve produced distal (long stump) or proximal (short stump) denervation. GLUT-4 levels and CS activities were measured at 24-h intervals for up to 96 h after denervation. No differences were observed in GLUT-4 or CS activity between soleus muscles left with short or long nerve stumps at any time point. However, within just 24 h, denervation decreased (P < 0.05) GLUT-4 and CS (67.4 ± 3.3 and 63.4 ± 1.7% of innervated control values, respectively). Both parameters continued to decline up to 96 h (44.4 ± 3.1 and 48.7 ± 4.0%, respectively). There was a significant correlation between the GLUT-4 protein level and CS activity over this 96-h period of denervation (r = 0.653, P < 0.001). A similar response in the 24-h denervated soleus of adult rats was observed. In contrast, 24-h denervation of red gastrocnemius (type IIa fibers) left with a long nerve stump resulted in a prevention of the decline of GLUT-4 and CS seen in red gastrocnemius left with a short nerve stump in both juvenile and adult animals. These results suggest that, unlike type IIa muscles, the decline in GLUT-4 level and CS activity in type I soleus muscle after denervation results from a lack of coordinated electrical activity but likely does not involve a neurotrophic agent. These results also support the hypothesis that there is coregulation of decreased expression of GLUT-4 protein and CS activity in this model of reduced neuromuscular activity.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume272
Issue number1 41-1
StatePublished - 1997

Fingerprint

Glucose Transporter Type 4
Citrate (si)-Synthase
Skeletal Muscle
Denervation
Muscle Denervation
Tibial Nerve
Facilitative Glucose Transport Proteins
Nerve Growth Factors
Muscles

Keywords

  • neurotrophic factors
  • reduced neuromuscular activity
  • sciatic nerve
  • tibial nerve
  • type I muscle fibers

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

Cite this

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title = "GLUT-4 protein and citrate synthase activity in distally or proximally denervated rat soleus muscle",
abstract = "The potential role of neurotrophic factors in the decline of glucose transporter (GLUT-4) protein levels and citrate synthase (CS) activity was studied by comparing distally with proximally denervated juvenile rat soleus muscle. Severing of the tibial nerve produced distal (long stump) or proximal (short stump) denervation. GLUT-4 levels and CS activities were measured at 24-h intervals for up to 96 h after denervation. No differences were observed in GLUT-4 or CS activity between soleus muscles left with short or long nerve stumps at any time point. However, within just 24 h, denervation decreased (P < 0.05) GLUT-4 and CS (67.4 ± 3.3 and 63.4 ± 1.7{\%} of innervated control values, respectively). Both parameters continued to decline up to 96 h (44.4 ± 3.1 and 48.7 ± 4.0{\%}, respectively). There was a significant correlation between the GLUT-4 protein level and CS activity over this 96-h period of denervation (r = 0.653, P < 0.001). A similar response in the 24-h denervated soleus of adult rats was observed. In contrast, 24-h denervation of red gastrocnemius (type IIa fibers) left with a long nerve stump resulted in a prevention of the decline of GLUT-4 and CS seen in red gastrocnemius left with a short nerve stump in both juvenile and adult animals. These results suggest that, unlike type IIa muscles, the decline in GLUT-4 level and CS activity in type I soleus muscle after denervation results from a lack of coordinated electrical activity but likely does not involve a neurotrophic agent. These results also support the hypothesis that there is coregulation of decreased expression of GLUT-4 protein and CS activity in this model of reduced neuromuscular activity.",
keywords = "neurotrophic factors, reduced neuromuscular activity, sciatic nerve, tibial nerve, type I muscle fibers",
author = "Fogt, {Donovan L.} and Slentz, {Michael J.} and Tischler, {Marc E} and Henriksen, {Erik J}",
year = "1997",
language = "English (US)",
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journal = "American Journal of Physiology",
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T1 - GLUT-4 protein and citrate synthase activity in distally or proximally denervated rat soleus muscle

AU - Fogt, Donovan L.

AU - Slentz, Michael J.

AU - Tischler, Marc E

AU - Henriksen, Erik J

PY - 1997

Y1 - 1997

N2 - The potential role of neurotrophic factors in the decline of glucose transporter (GLUT-4) protein levels and citrate synthase (CS) activity was studied by comparing distally with proximally denervated juvenile rat soleus muscle. Severing of the tibial nerve produced distal (long stump) or proximal (short stump) denervation. GLUT-4 levels and CS activities were measured at 24-h intervals for up to 96 h after denervation. No differences were observed in GLUT-4 or CS activity between soleus muscles left with short or long nerve stumps at any time point. However, within just 24 h, denervation decreased (P < 0.05) GLUT-4 and CS (67.4 ± 3.3 and 63.4 ± 1.7% of innervated control values, respectively). Both parameters continued to decline up to 96 h (44.4 ± 3.1 and 48.7 ± 4.0%, respectively). There was a significant correlation between the GLUT-4 protein level and CS activity over this 96-h period of denervation (r = 0.653, P < 0.001). A similar response in the 24-h denervated soleus of adult rats was observed. In contrast, 24-h denervation of red gastrocnemius (type IIa fibers) left with a long nerve stump resulted in a prevention of the decline of GLUT-4 and CS seen in red gastrocnemius left with a short nerve stump in both juvenile and adult animals. These results suggest that, unlike type IIa muscles, the decline in GLUT-4 level and CS activity in type I soleus muscle after denervation results from a lack of coordinated electrical activity but likely does not involve a neurotrophic agent. These results also support the hypothesis that there is coregulation of decreased expression of GLUT-4 protein and CS activity in this model of reduced neuromuscular activity.

AB - The potential role of neurotrophic factors in the decline of glucose transporter (GLUT-4) protein levels and citrate synthase (CS) activity was studied by comparing distally with proximally denervated juvenile rat soleus muscle. Severing of the tibial nerve produced distal (long stump) or proximal (short stump) denervation. GLUT-4 levels and CS activities were measured at 24-h intervals for up to 96 h after denervation. No differences were observed in GLUT-4 or CS activity between soleus muscles left with short or long nerve stumps at any time point. However, within just 24 h, denervation decreased (P < 0.05) GLUT-4 and CS (67.4 ± 3.3 and 63.4 ± 1.7% of innervated control values, respectively). Both parameters continued to decline up to 96 h (44.4 ± 3.1 and 48.7 ± 4.0%, respectively). There was a significant correlation between the GLUT-4 protein level and CS activity over this 96-h period of denervation (r = 0.653, P < 0.001). A similar response in the 24-h denervated soleus of adult rats was observed. In contrast, 24-h denervation of red gastrocnemius (type IIa fibers) left with a long nerve stump resulted in a prevention of the decline of GLUT-4 and CS seen in red gastrocnemius left with a short nerve stump in both juvenile and adult animals. These results suggest that, unlike type IIa muscles, the decline in GLUT-4 level and CS activity in type I soleus muscle after denervation results from a lack of coordinated electrical activity but likely does not involve a neurotrophic agent. These results also support the hypothesis that there is coregulation of decreased expression of GLUT-4 protein and CS activity in this model of reduced neuromuscular activity.

KW - neurotrophic factors

KW - reduced neuromuscular activity

KW - sciatic nerve

KW - tibial nerve

KW - type I muscle fibers

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