title: Renal metabolism and urinary excretion of thromboxane B2 in the rat.
abstract: We wanted to evaluate whether the kidney tissue can metabolize thromboxane (Tx) B2 and, specifically, whether the 2,3-dinor metabolite might be formed in the kidney and excreted in the urine. For this purpose, we used an isolated perfused kidney preparation exposed to vehicle or TxB2 at different infusion rates. Approximately 96% of the total TxB2 infused was recovered in the venous effluent, whereas approximately 1% was found in urine. Isolated perfused kidneys exposed to [3H]TxB2 eliminated in the urine 1.2% of the [3H]TxB2 infused, measured by thin-layer chromatographic analysis, and actively metabolized [3H]TxB2 to 2,3-dinor-TxB2, 11-dehydro-TxB2, and possibly 2,3,4,5-tetranor-TxB1. No metabolites of TxB2 were recovered in the venous effluent. As a marker of renal TxB2 metabolic activity, urinary 2,3-dinor-TxB2 was quantified by high-resolution gas chromatography-negative-ion chemical ionization mass spectrometry. The 2,3-dinor-TxB2 was detected both before and during TxB2 infusion in urinary samples but not in the venous effluent. The ratio of 2,3-dinor-TxB2-TxB2 increased during the infusion reaching a peak value immediately after stopping the TxB2 infusion. These results indicate that, in the rat, the kidney tissue metabolizes TxB2 to 2,3-dinor-TxB2, and both TxB2 and 2,3-dinor-TxB2 are excreted in the urine.
authors.affiliation: Mario Negri Institute for Pharmacological Research, Bergamo, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Benigni
authors.forename: C
authors.initials: C
authors.lastname: Chiabrando
authors.forename: N
authors.initials: N
authors.lastname: Perico
authors.forename: R
authors.initials: R
authors.lastname: Fanelli
authors.forename: C
authors.initials: C
authors.lastname: Patrono
authors.forename: G A
authors.initials: GA
authors.lastname: FitzGerald
authors.forename: G
authors.initials: G
authors.lastname: Remuzzi
mesh_terms: D000818:Animals; D001241:Aspirin / Q000494:pharmacology; D007668:Kidney / Q000378:metabolism*; D010477:Perfusion; D051381:Rats; D011919:Rats, Inbred Strains; D013929:Thromboxane B2 / Q000378:metabolism*
chemical_list: D013929:Thromboxane B2; D001241:Aspirin