Effect of post-exercise lactate administration on glycogen repletion and signaling activation in different types of mouse skeletal muscle.
Level 5 - mechanism / opinion, no new human data
Animal research (in vivo mouse model)
PubMed 34746818 · doi:10.1016/j.crphys.2020.07.002
What was done
Eight-week-old male ICR mice were fasted overnight for 16 hours and subjected to 60 minutes of treadmill running at 20 m/min. Immediately post-exercise, mice received an intraperitoneal injection of either phosphate-buffered saline or sodium lactate (1 g/kg body weight) paired with oral administration of water or glucose (2 g/kg body weight). Skeletal muscles (soleus, plantaris, gastrocnemius) and signaling proteins were evaluated after 60 minutes of recovery.
What was found
Glucose ingestion increased glycogen content across the soleus, plantaris, and gastrocnemius muscles. Concomitant lactate injection produced an additive increase in glycogen content in the plantaris and gastrocnemius muscles, but had no additive effect in the soleus. No exact numerical values or confidence intervals were reported in the abstract. Lactate administration did not significantly alter glucose uptake- or oxidation-related proteins in the plantaris, though it enhanced TBC1D1 phosphorylation in the soleus. FBP2 protein was significantly higher in plantaris and gastrocnemius versus soleus, whereas MCT1 protein was higher in the soleus.
Why it matters
The findings suggest that elevated lactate combined with post-exercise carbohydrate intake can additively promote glycogen recovery in glycolytic skeletal muscle types, potentially linked to glyconeogenic capacity.
Limits
The study was conducted exclusively in male mice using an intraperitoneal injection of lactate, limiting direct translational relevance to oral human nutrition. Exact animal numbers, baseline glycogen levels, and numerical effect sizes were not reported in the abstract, and observations were limited to a single 60-minute recovery timepoint.
Cited by
- supports Lactate produced during vigorous exercise signals the increase in GLUT4 glucose transporters and their translocation to the muscle cell surface.