Steady-state Serum Levels Research Articles

Absorption of digoxin in patients with malabsorption syndromes.

Abstract Gastrointestinal absorption of digoxin was evaluated by use of a recently developed radioimmunoassay to measure serum levels. Eleven patients with malabsorption syndrome (nine with malabsorption and two with maldigestion due to pancreatic insufficiency) were compared with a control group of 10 patients who had no intestinal disease. All subjects received 0.25 mg of oral digoxin daily, and steady-state serum levels, reached after six days in all subjects, were determined. The mean steady-state serum digoxin level for the nine patients with malabsorption was significantly less than that for the control group (p less than 0.001), whereas levels for the two patients with pancreatic insufficiency were not significantly different from control values. These data indicate that digoxin is poorly and erratically absorbed by patients with malabsorption on the basis of mucosal defects or hypermotility but may be more normally absorbed by patients with pancreatic insufficiency.

Distribution of α-aminoisobutyric-C 14 acid in rats deficient in thiamine, pantothenate, fatty acids, or potassium

A nutritional deficiency of fatty acids in young rats resulted in a marked elevation of the steady-state serum level of an injected dose of α-aminoisobutyric acid, and in a decrease in the transport of this model amino acid into skeletal muscle, heart, and intestine. The liver level was greatly increased. Adrenalectomy of the deficient rats reduced the uptake in both liver and kidney. These changes were similar to those reported earlier for rats deficient in vitamin B 6. No consistent pattern of change in distribution of the model amino acid was found in rats deficient in thiamine, pantothenate, or potassium. The extremely high liver levels of the amino acid seen in thiamine-deficient rats could be returned toward normal by removing the adrenal glands. All of the changes found in the K +-deficient animals were brought essentially to normal by bilateral adrenalectomy. No consistent relationship was found between the uptake of the amino acid and the K + level in the heart or skeletal muscle of the rats in the control, K +-deficient, and the K +-deficient adrenalectomized groups.