Die Bestimmung der intestinalen Resorption von Herzglykosiden durch Messung der 3H-markierten Glykoside im Portalvenenblut und in der Darmlymphe bei Katzen
SchlüsselwörterIntestinale Resorption Herzglykoside Portalvenenblut Darmlymphe Katze
The cardiac glycosides digitoxin, ouabain, digoxin and peruvosid labelled with 3H were injected into tied intestinal loops of anaesthetized cats in situ. The absorbed glycosides were measured in the blood of the portal vein and in the intestinal lymph. At the same time the 3H-activity was measured in the blood of the peripheral circulation, in the bile and in the urine.
Calculation of the amount of glycosides totally absorbed from the 3H-concentration in the blood of the portal vein and the circulation volume (bubble-flow-meter) gave the following absorption rates as a percentage of the administered dose per hour: digitoxin 56%, digoxin 42%, peruvosid 26% and ouabain 10%.
The amount of glycosides passing into the lymph during 1 hour was found to be only 0.006 to 0.02% of the amount offered. In lymph 3H-activity cannot be measured earlier than 5 min after the administration of the labelled glycosides. The 3H-concentration in the lymph did not equal that measured in the blood of the peripheral circulation until at least 1 hour after the administration and always remained below the 3H-concentration of the blood in the portal vein. This proportion remained unchanged even if digitoxin was administered as an emulsion in oil instead of an aqueous solution. From the time course of 3H-concentration it might be concluded that the glycosides do not pass directly to the lymph after absorption but indirectly by way of the blood.
The amount of glycoside excreted in the bile is for peruvosid 15, 5% of the amount absorbed, for ouabain 1, 9%, for digoxin 1, 4% and for digitoxin 0, 8%. The 3H-activity excreted in urine is very small and can be disregarded.
Chromatographic analyses of the bile revealed, that in the case of digoxin, 4/5 of the amount excreted were unchanged, in the case of digitoxin and ouabain 2/3 and in the case of peruvosid only ¼. In the lumen of the tied intestinal loops and in the tissue of the small intestine the glycosides were hardly metabolised.
Key-WordsIntestinal Absorption Cardiac Glycosides Blood of Portal Vein Intestinal Lymph Cat
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