Role of local contractile activity and muscle fiber type on LPL regulation during exercise

Am J Physiol. 1998 Dec;275(6):E1016-22. doi: 10.1152/ajpendo.1998.275.6.E1016.

Abstract

The purpose of this study was to determine the influence of local contractile activity on lipoprotein lipase (LPL) regulation in skeletal muscle. Short-term voluntary run training increased LPL mRNA concentration and LPL immunoreactive mass about threefold in white skeletal muscles of the rat hindlimb (all P < 0.01). Training also increased total and heparin-releasable LPL enzyme activity in white hindlimb muscles and in postheparin plasma (P < 0.05). Training did not enhance LPL regulation in a white muscle that was not recruited during running (masseter). LPL levels were already high in red skeletal muscles of control rats, and training did not result in a further rise. In resting rats, local electrical stimulation of a motor nerve to a predominantly white muscle caused a significant rise in LPL mRNA, immunoreactive mass, and enzyme activity relative to the contralateral control muscle of the same animals (all P < 0.01). Finally, LPL expression was several times greater in a red muscle (soleus) of rats with normal postural activity than rats with immobilized hindlimbs (P < 0.01). In summary, these studies support the hypothesis that local contractile activity is required for increasing LPL expression during exercise training and for maintaining a high level of LPL expression in postural muscles.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Electric Stimulation
  • Female
  • Heparin / pharmacology
  • Hindlimb
  • Immobilization
  • Lipoprotein Lipase / genetics
  • Lipoprotein Lipase / metabolism*
  • Motor Activity / physiology*
  • Muscle Contraction / physiology*
  • Muscle Fibers, Skeletal / classification
  • Muscle Fibers, Skeletal / physiology*
  • Muscle, Skeletal / drug effects
  • Muscle, Skeletal / enzymology
  • Physical Conditioning, Animal
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Running / physiology

Substances

  • RNA, Messenger
  • Heparin
  • Lipoprotein Lipase