Alterations in plasma levels of apolipoprotein A-IV in various clinical entities.

The serum levels of apolipoprotein A-IV (apo A-IV) were measured by rocket immunoelectrophoresis in disease-free humans, at fasting and after oral and intravenous fat administration. The studies were extended to patients with chronic pancreatitis, malabsorption syndrome, to postoperative patients on total parenteral nutrition and to patients with liver diseases, cholestasis, diabetes mellitus and chronic renal failure. Oral fat ingestion resulted in an increase of apo A-IV levels which remained elevated even when the postprandial hypertriglyceridemia had disappeared. A transient increase in apo A-IV levels was observed after intravenous fat infusion but the level declined simultaneously with decreases in triglyceride levels. Levels of serum apo A-IV were decreased under conditions where decreased fat intake or malabsorption of nutrients might have been present, such as in patients with chronic pancreatitis, malabsorption syndrome, acute hepatitis in the early stage, obstructive jaundice and in postoperative patients on total parenteral nutrition. On the other hand, the apo A-IV levels were high in patients with chronic renal failure and in those with diabetes mellitus and proteinuria.