Creatine analogue beta-guanidinopropionic acid alters skeletal muscle AMP deaminase activity

Am J Physiol. 1996 Jan;270(1 Pt 1):C76-85. doi: 10.1152/ajpcell.1996.270.1.C76.

Abstract

Dietary supplementation of the creatine analogue beta-guanidinopropionic acid (beta-GPA) decreases in vitro skeletal muscle AMP deaminase (AMP-D) activity in rats. Downregulation of AMP-D activity was progressive and greater in fast-twitch muscles (70-80%) than in the slow-twitch soleus muscle (approximately 50%). The loss in AMP-D activity had little effect on inosine 5'-monophosphate accumulation in mixed-fiber muscle with intense tetanic contractions. In contrast, inosine 5'-monophosphate formation was evident earlier in fast-twitch red and white fiber sections of creatine-depleted animals during intense twitch contractions, indicating that fast-twitch muscle of beta-GPA-treated rats buffers decreases in the ATP/ADPfree ratio via deamination, even though AMP-D activity is less. Isoforms of skeletal muscle AMP-D mRNAs in mixed-fiber muscle were not altered by feeding beta-GPA for up to 9 wk. Creatine depletion did not alter total immunoreactivity; however, a redistribution of AMP-D immunoreactivity from primarily an approximately 80-kDa form toward lower apparent molecular mass species (approximately 60 and approximately 56 kDa) was observed. Posttranslational changes in AMP-D appear related to changes in activity.

Publication types

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

MeSH terms

  • AMP Deaminase / antagonists & inhibitors
  • AMP Deaminase / metabolism*
  • Animals
  • Blotting, Northern
  • Blotting, Western
  • Creatine / analogs & derivatives
  • Deamination
  • Electric Stimulation
  • Enzyme Activation
  • Guanidines / pharmacology*
  • Male
  • Muscle, Skeletal / drug effects*
  • Muscle, Skeletal / enzymology*
  • Nucleic Acid Hybridization
  • Propionates / pharmacology*
  • Rats
  • Rats, Sprague-Dawley
  • Ribonucleases
  • Time Factors

Substances

  • Guanidines
  • Propionates
  • Ribonucleases
  • AMP Deaminase
  • Creatine
  • guanidinopropionic acid