Effects of high-intensity intermittent training on carnitine palmitoyl transferase activity in the gastrocnemius muscle of rats.
Level 5 - mechanism / opinion, no new human data
Animal research without human clinical data
PubMed 22735180 · doi:10.1590/s0100-879x2012007500105
What was done
Male adult Wistar rats (N = 25, 160-250 g) were randomly assigned to three groups: sedentary (Sed, n = 5), high-intensity intermittent training (HI-IT, n = 10, 10% overload), and moderate-intensity continuous training (MI-CT, n = 10, 5% overload). After 8 weeks of exercise, researchers measured gastrocnemius muscle maximal activities of carnitine palmitoyl transferase I and II (CPT-I, CPT-II), citrate synthase, and lactate dehydrogenase (LDH), as well as gene expression of fatty acid binding protein (FABP) and lipoprotein lipase (LPL) via RT-PCR, alongside body weight gain.
What was found
Compared with the Sed group, the HI-IT group showed an 11.8% decrease in weight gain. HI-IT significantly increased maximal activities of CPT-I, CPT-II, and citrate synthase (all P < 0.01), as well as gene expression of FABP (P < 0.01) and LPL (P < 0.05). LDH maximal activity was also higher in HI-IT (around 83%). The abstract reports no numerical values or statistical comparisons for the MI-CT group.
Why it matters
The study shows that high-intensity interval training upregulates key enzyme systems and transport proteins involved in mitochondrial lipid uptake and oxidation in rodent skeletal muscle.
Limits
This is an animal study in male rats, limiting generalizability to humans. The sample size was small, especially in the sedentary control group (n = 5). The abstract reports no numerical data, variance, or comparison results for the moderate-intensity continuous training group.
Cited by
- supports Both moderate-intensity and vigorous-intensity exercise increase carnitine palmitoyltransferase (CPT) enzyme capacity in muscle.