Effect of serum albumin on vascular smooth muscle metabolism.
In studies on metabolism of vascular smooth muscle, it was observed that incubation of intact porcine carotid artery strips with 3% bovine or porcine serum albumin had profound effects on the oxidation of substrates and O2 consumption. Arteries incubated over 180 min with charcoal-treated and dialyzed albumin demonstrated time-dependent stimulation of glucose oxidation (145%; P < 0.0001, n=6) and O2 consumption (116%; P< 0.001, n=6). These results were not mimicked by incubation with 3% solutions of ovalbumin or porcine skin gelatin. However, the oxidation of the medium chain fatty acid octanoate was inhibited in the presence of albumin over a broad range of octanoate concentrations (0.5-5.0 mM). Short chain fatty acid oxidation (acetate, 5 mM), in contrast, was not inhibited by albumin. Wash-out of albumin only partially reversed the stimulation of O2 consumption and incubation of arteries with a polyanionic compound, polyethylene sulfonate (5 mg/ml), blunted the stimulatory effect of albumin on O2 consumption. Albumin also produced anaplerosis of the Krebs cycle, and an increase in the content of glutamate and alanine (P < 0.005, n=8). The metabolic effects of albumin were associated with time-dependent uptake of albumin (30.9 +/- 1.5 nmol/g per 210 min; P<0.01, n=15). ATP-dependent proteolysis of the albumin taken up was also observed. These results demonstrate novel and important intracellular effects of serum albumin on energy metabolism of vascular smooth muscle.
Barron
J T
JT
Department of Medicine, and Rush Medical College, Rush-Presbyterian-St. Luke's Medical Center, Chicago, IL 60612, USA. jbarron@rush.edu
Gu
L
L
Rodriguez
E R
ER
Parrillo
J E
JE
D000085:Acetates / Q000737:chemistry; D000818:Animals; D002210:Caprylates / Q000737:chemistry; D002339:Carotid Arteries; D002952:Citric Acid Cycle / Q000187:drug effects; D005947:Glucose / Q000737:chemistry / Q000378:metabolism*; D018698:Glutamic Acid / Q000032:analysis; D066298:In Vitro Techniques; D009131:Muscle, Smooth, Vascular / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D010084:Oxidation-Reduction; D010101:Oxygen Consumption / Q000187:drug effects; D010168:Palmitates / Q000737:chemistry; D012709:Serum Albumin / Q000378:metabolism* / Q000494:pharmacology; D012710:Serum Albumin, Bovine / Q000378:metabolism / Q000494:pharmacology; D013552:Swine
D000085:Acetates; D002210:Caprylates; D010168:Palmitates; D012709:Serum Albumin; D012710:Serum Albumin, Bovine; D018698:Glutamic Acid; D005947:Glucose; C031492:octanoic acid