Effects of L-leucine on palmitate metabolism and insulin release by isolated islets of fed and starved rats.
The occurrence of lipid metabolic changes associated with L-leucine (10 mM) stimulation of insulin release was investigated in isolated islets from either fed or starved rats. L-Leucine-stimulated secretion was potentiated by 3 mM glucose and/or 0.5 mM palmitate and was unaffected by 48 h of starvation. Islet palmitate oxidation showed a maximum rate at 3 mM glucose, and starvation increased it almost 2-fold. Regardless of the nutritional state, L-leucine strongly reduced the oxidation of palmitate and increased its incorporation into islet triacylglycerols and phospholipids at 3 mM glucose. This shift of fatty acid metabolism toward esterification might play a role in the mechanism of potentiation of the islet secretory response to L-leucine by glucose and palmitate.
D000818:Animals; D004435:Eating; D005947:Glucose / Q000494:pharmacology; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism*; D007930:Leucine / Q000494:pharmacology*; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000378:metabolism* / Q000494:pharmacology; D010743:Phospholipids / Q000096:biosynthesis; D051381:Rats; D011919:Rats, Inbred Strains; D012636:Secretory Rate / Q000187:drug effects; D013217:Starvation / Q000378:metabolism*; D014280:Triglycerides / Q000096:biosynthesis
D007328:Insulin; D010169:Palmitic Acids; D010743:Phospholipids; D014280:Triglycerides; D019308:Palmitic Acid; D007930:Leucine; D005947:Glucose