Note in Science page
Created Aug 04 08, Updated Mar 05 10 14:48
Exercise mimetics go to comments

Muscle-enhancing drugs: tricking muscles into thinking they have been working out.

AMPK-PPARδ pathway can be targeted by orally active drugs to enhance training adaptation or even to increase endurance without exercise; representing a novel pharmacologic target to reprogram muscle endurance.

Last year researcher from the Salk Institute for Biological Studies in San Diego have shown that genetically engineered mice with increased PPARδ (a master regulator of numerous genes) activity had almost double the running endurance of regular mice. Now the same team tested the effect of PPARδ and AMPK agonists.
One drug, Aicar (AMPK agonist), increased the mice’s running distance on a treadmill by 44 percent after just four weeks of treatment without any form of exercise training! A second drug, GW1516 (PPARδ agonist, developed by GlaxoSmithKline to raise levels of HDL), increases running distance by 70% but had to be combined with exercise to have any effect.

They showed that the AMP-mimetic AICAR can increase endurance in sedentary mice by genetically reprogramming muscle metabolism in a PPARδ – dependant manner.
Aicar appeard to change the physical composition of muscle, transforming the tissue from sugar-burning fast-twitch fibers to fat-burning slow-twitch ones, the same changes that occur through heavy endurance training.


5-aminoimidazole-4-carboxamideribonucleotide (AICAR)

Cell article [AMPK and PPARδ Agonists Are Exercise Mimetics]
sciencenow link
nytimes link
latimes link

~related story: Mighty Mice; myostatin and follistatin regulation of muscle build up: sciencedaily link


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