Regulation of urinary thromboxane B2 in man: influence of urinary flow rate and tubular transport

Journal Article · Wed Feb 01 04:00:00 EST 1984 · Prostaglandins; (United States)

DOI:https://doi.org/10.1016/0090-6980(84)90078-9· OSTI ID:6746960

Zipser, R D; Smorlesi, C

Thromboxane B2 (TxB) is excreted in human urine, but the mechanism of renal excretion and the quantitative relationship of urinary TxB to the active parent compound, thromboxane A2, of renal or extrarenal origin is not established. To determine the effects of vasoactive hormones, uricosuric agents and urinary flow rate on TxB excretion, urinary TxB was measured by radioimmunoassay and mass spectrometry, and renal metabolism of blood TxB was determined by radiochromatography of urine after i.v. (3H)-TxB infusions. Basal TxB was 6.7 +/- 1.1 ng/h during an oral water load, and TxB fell with s.g. antidiuretic hormone (to 3.4 +/- 0.4 ng/h, P less than 0.01) and with fluid restriction (to 2.6 +/- 0.5 ng/hr, P . 0.001) in parallel with urinary volume. Urinary excretion of unmetabolized (3H)-TxB also fell (by 56%) with fluid restriction, implicating altered metabolism rather than synthesis as the mechanism of the urinary flow effect. Angiotensin II infusions slightly reduced both TxB and urine volume, consistent with a flow effect. In contrast, probenecid did not alter urine volume, but increased urinary uric acid (by 244%), TxB (from 5.6 +/- 0.9 to 11.1 +/- 2.9 ng/h) and urinary excretion of blood (3H)-TxB (by 243%) by similar amounts (all P less than 0.05), suggesting that TxB is actively reabsorbed in the proximal tubule, similarly to uric acid. Thus, urinary excretion of TxB of renal and extrarenal origin is regulated by proximal and distal tubule factors.

• Research Organization: Department of Medicine, University of Southern California, Los Angeles County Medical Center
• OSTI ID: 6746960
• Journal Information: Prostaglandins; (United States), Journal Name: Prostaglandins; (United States) Vol. 27:2; ISSN PRGLB
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
ANGIOTENSIN
ARACHIDONIC ACID
BIOLOGICAL MATERIALS
BIOLOGICAL WASTES
BODY FLUIDS
CARBOXYLIC ACIDS
CARDIOVASCULAR AGENTS
CHROMATOGRAPHY
CLEARANCE
DRUGS
EXCRETION
GLOBULINS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MASS SPECTROSCOPY
MATERIALS
METABOLISM
METABOLITES
MONOCARBOXYLIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
PROSTAGLANDINS
PROTEINS
RADIOASSAY
RADIOCHROMATOGRAPHY
RADIOIMMUNOASSAY
RENAL CLEARANCE
SEPARATION PROCESSES
SPECTROSCOPY
TRACER TECHNIQUES
TRITIUM COMPOUNDS
URINE
VASOCONSTRICTORS
WASTES