ISSN:
1432-1912
Keywords:
Cardioglycoside
;
Labelled Compound
;
Drug Metabolism
;
Pharmacokinetics
;
Absorption
;
Gastrointestinal
;
Herzglykosid
;
Radioaktive Markierung
;
Pharmakokinetik
;
Arzneimittelmetabolismus
;
Resorption
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary Helveticosol-3H-acetonid (HA) was given to guinea-pigs under urethane anaesthesia by intravenous or intraduodenal injection and by intravenous or intraportal infusion. Blood levels of radioactivity were assayed during, and tissue content, biliary excretion and metabolites at the end of, the experiment. 1. During the first minutes of intravenous of intraportal infusion, blood levels depended on the mode and rate of administration. At equal rates of infusion, a higher distribution volume was found on intraportal than on intravenous infusion. With decreasing rates of infusion, distribution volume increased on intraportal, but decreased on intravenous administration. These differences disappeared within two hours. 2. HA was rapidly metabolized. Twenty minutes after an intravenous injection, little unchanged compound was retrieved from the blood. The same metabolites were found after intraduodenal injection. There was no difference between toxic doses on intraportal and intravenous infusion suggesting that HA is not inactivated during a single passage through the liver after absorption from the intestine 3. The ratio of absorption was calculated from the radioactivity remaining in the duodenum and from a comparison of the blood levels after intraduodenal injection and intraportal infusion. After two hours absorption was between 55 and 78%. Assuming an exponential absorption from the intestine, a half life of about 30 min was found during the first 20 min after indraduodenal injection. The speed of absorption decreased in the course of the experiment. 4. Following intraduodenal injection of a toxic dose, arrhythmias were accompanied by higher blood levels than on intravenous infusion. This is attributed to the shorter time-lag with which these symptoms set in after intraduodenal injection. During the infusion of lethal doses, the blood levels rose abruptly during the last minutes before death, indicating a diminution in distribution volume due to a decrease in tissue blood flow. 5. Excretion of radioactivity with the bile was particularly rapid during the first minutes after the administration of high doses. The lowest biliary clearance was observed during slow intraportal infusion.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00997784
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