11-Dehydro thromboxane B2: a reliable parameter of thromboxane A2 production in dogs.
Plasma concentration of 11-dehydro thromboxane B2 (TxB2) is reported to be a reliable indicator of TxA2 production in human and rabbit. The purpose of this study is to examine whether we can use this parameter in dogs. The plasma concentration of 11-dehydro TxB2 was determined by enzyme immunoassay method using anti-11-dehydro TxB2 monoclonal antibody. When 10 micrograms/kg of TxB2 was intravenously administered to dogs in which endogenous production of prostanoids was blocked by aspirin, the plasma concentrations of 11-dehydro TxB2 before and 2, 5, 15, 60 min after TxB2 administration were 6.2 +/- 1.4, 54.2 +/- 5.0, 65.2 +/- 14.3, 65.2 +/- 16.4 and 31.0 +/- 7.5 pg/ml, while the corresponding TxB2 levels were 20.1 +/- 3.1, 3143.3 +/- 379.5, 1432.6 +/- 120.5, 356.8 +/- 38.9, and 128.9 +/- 13.6 pg/ml, respectively. Platelet-activating factor (PAF, 0.5 micrograms/kg) induced pulmonary vasoconstriction which was blocked by aspirin and OKY-046 (TxA2 synthetase inhibitor), indicating that TxA2 mediated this change. Plasma concentration of 11-dehydro TxB2 was increased by PAF. This change was also blocked by aspirin and OKY-046. These data suggest that the determination of plasma concentration of 11-dehydro TxB2 is useful to estimate the in vivo production of TxA2 in dogs.
Yamanaka
S
S
Department of Pharmacology, Osaka City University Medical School, Japan.
Miura
K
K
Yukimura
T
T
Yamamoto
K
K
D000818:Animals; D004285:Dogs; D005260:Female; D008168:Lung / Q000098:blood supply; D008297:Male; D010972:Platelet Activating Factor / Q000494:pharmacology; D015203:Reproducibility of Results; D013928:Thromboxane A2 / Q000096:biosynthesis*; D013929:Thromboxane B2 / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics; D014655:Vascular Resistance / Q000187:drug effects
D010972:Platelet Activating Factor; D013929:Thromboxane B2; D013928:Thromboxane A2; C049235:11-dehydro-thromboxane B2