Palmitate incorporation into lipids pools of contracting red and white muscles.
We compared the incorporation of the blood-borne [14C]-palmitate into selected lipid and phospholipid pools in rat muscles (soleus, red and white gastrocnemius), at rest and during contractions (15 and 60 tetani/min) in one leg (5 min) while the contralateral leg served as a control. [1-(14)C]-palmitate (20 microCi/rat) was administered into the carotid artery (t = 1 min). [14C]-palmitate deposition was greatest in soleus (100%) and lower in red (82%) and white gastrocnemius muscles (63%), respectively (p < 0.05). [14C] was deposited primarily into the tri-acylglycerol (approximately 50%) and phospholipid pools (approximately 30%) of soleus and red gastrocnemius muscles, and into the di-acylglycerol (approximately 30%), tri-acylglycerol (approximately 30%) and phospholipid pools (approximately 30%) in white gastrocnemius muscle. During contraction the concentrations of tri-acylglycerol were not changed. But, contraction increased [14C]-palmitate incorporation into soleus and red gastrocnemius muscles (600-700%) and into white gastrocnemius muscles (200%). Slightly more [14C] was directed from the phospholipids into the tri-acylglycerol pool during contraction. [14C]-palmitate deposition was also increased in the subclasses of phospholipids during contraction in red and white gastrocnemius. In conclusion, the deposition of [14C]palmitate into different lipid and phospholipid pools is quite rapid, and is dependent on contraction and the muscle fiber type.
Gorski
J
J
Department of Physiology, Medical Academy, Poland.
Bonen
A
A
D000818:Animals; D002250:Carbon Radioisotopes; D004075:Diglycerides / Q000378:metabolism; D004558:Electric Stimulation; D050356:Lipid Metabolism; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D009126:Muscle Relaxation / Q000502:physiology*; D018482:Muscle, Skeletal / Q000378:metabolism*; D019308:Palmitic Acid / Q000097:blood / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism; D051381:Rats; D012584:Sciatic Nerve; D014018:Tissue Distribution; D014280:Triglycerides / Q000378:metabolism
D002250:Carbon Radioisotopes; D004075:Diglycerides; D010743:Phospholipids; D014280:Triglycerides; D019308:Palmitic Acid