Tissue distribution, elimination, and metabolism of [3H]leukotriene C4 by the conscious marine toad, Bufo marinus.
Tissue distribution, elimination, and metabolism of 3H-labelled leukotriene (LT) C4 were studied in ureter-catheterized conscious marine toads, Bufo marinus. Six and 24 h after injection, organs containing the highest percent of injected radioactivity were small intestine, liver, and kidney. Radioactivity declined in these organs at 24 h by approximately threefold. Peak elimination time for radioactivity in the urine was between 2 and 4 h after the injection. During the 24-h collection period, 55.2 +/- 0.2% of the injected radioactivity was eliminated in the urine. Polar metabolites represented 40.3 +/- 1.1, 57.3 +/- 5.6, and 62.8 +/- 1.6% of the radioactivity at 2, 4, and 6 h, respectively. The primary urinary polar metabolite was 20-carboxy-LTE4, with 18-carboxydinor-LTE4 and 20-hydroxy-LTE4 also present. [3H]LTE4 decreased from 37.2 +/- 1.8% at 2 h to 15.8 +/- 3.3 and 15.0 +/- 2.1% of the radioactivity at 4 and 6 h, respectively. Bile radioactivity was low. N-Acetyl-LTE4 was not detected in urine or bile samples. Radioactivity in the pan water was 14.3 +/- 2.4 and 15.8 +/- 2.5% of the injected radioactivity, at 6 and 24 h, respectively, suggesting that the skin was a route for excretion of leukotrienes. The marine toad is an interesting model demonstrating both similarities and differences from mammals in distribution, elimination, and metabolism of peptide leukotrienes.
Pfeifer
C A
CA
Department of Biology, New Mexico State University, Las Cruces 88003.
Furilla
R A
RA
Gronert
K
K
Goss
D D
DD
Herman
C A
CA
D000818:Animals; D001646:Bile / Q000378:metabolism; D002024:Bufo marinus; D002404:Catheterization; D002851:Chromatography, High Pressure Liquid; D005260:Female; D007421:Intestine, Small / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism*; D017999:Leukotriene E4; D008099:Liver / Q000378:metabolism*; D008297:Male; D013189:SRS-A / Q000031:analogs & derivatives / Q000378:metabolism / Q000493:pharmacokinetics*; D014018:Tissue Distribution
D013189:SRS-A; D017999:Leukotriene E4