Pharmacological action of CV-6504(HCI), a triple inhibitor of thromboxane (TXA2), leukotrienes (LTs) and free radicals

715

~h~~a~~l~ica~

action af CV-65 Cm),a triple iRh~b~t~r of leukotrienes (LTs) and free radicals

Terashita,

Z.-f., Imura, Y., Shibouta,

J3iofowResearch ~~rat~~e~

Y., Ohkawa

and * Chemistry Research ~borat~rie~

*, S. and Nishikawa,

K.

Takeda Chen~~~,a~ Industries, Ltd. Osaka, Japan

The pathophysiological roles of various chemical mediators such as TXA,. LTs and free radicals and their interactions in many diseases including glomerulonephritis have been recognized. Thus, it expected that multi-inhibitors of these chemical mediators would be more effective in the treatment of diseases than the pure inhibitors for indivisual mediator. We have developed a unique triple inhibitor, CV-6504 (HCI), which inhibits the biosynthesis of both TXA, and LTs and scavenges free radicals. In vitro: CV-6504(HCl) inhibited TXA, synthetase (horse platelet microsomes) and S-lipoxygenase (rat basophific leukemia cells) with I& values of 0.4 and 0.02 PM. respectively, but had no effect on PGI, synthetase (bovine aortic microsomes) or IZlipoxygenase (rat platelets). CV-6504(HCl) inhibited the generation of TXA, and LTB, with IC, vaIues of 0.34 and 0.45 FM, respectively, with a concomitant increase in the generation of PGI, in human whole blood stimuIated with A 23187. ~V-65~H~l) also inhibited the generation of malondialdehyde (MDA) in rat brain homogenates and kidney slices with IC,, of 1.8 and 0.5 PM, respectively. Ex vivo and in vivo: In rat ex vivo experiments, CV-6504(HCl) at 1 to 20 mg/kg (p.0.) reduced serum TXB, and increased serum 6-keto-PGF,a in a dose-dependent manner. Puromycin aminonucleoside (PAN) (100 mg/kg. i.p.) induced massive proteinuria, increased in plasma and urine levels of MDA and enhanced of renal biosynthesis of TXA, and LTs from arachidonic acid in rats. Oral administration of CV-65~HCl)(lO mg/kg/day) for 2 weeks corrected the protein&a, reduced the MDA levels and inhibited the biosynthesis of TXA, and LTs in this nephrotic rats. In conclusion, C’V-6504(HCl) exhibits a triple inhibitory action. The beneficial effect of CV-6504JHCI) in PAN-treated rats may be related to its triple inhibitory action. CV-6504(HCI) could be a new type of drug for the treatment of giomerular diseases.

I

P.tu.019

Separation of ~~stacyc~in and th~o~boxa~e ~~tab~~itesby Vapaatalo,

H. and Riutta,

A.

Department of B, medical Sciences, University 01 Tampere, PO Box 607, SF-33101 Tcampere. Finland

The main cycle-oxygenase product of arac~donic acid in the vessels is prostacyc~in (PGI,), a powerful anti-aggregatory and vasodilatory agent, Thromboxane A, (TXA,) is a potent platelet aggregating and vasocoustrictory substance produced from arachidonic acid by platelets. Direct measurements of these unstable compounds is extremely difficult. Their non-enzymatic metabolites 6-keto-PGF,, and TXB, are not good targets for measurements at least from plasma due 10 artifactual formation during blood sampling. In urine. they are prodsced by the kidneys, rather than filtrated from plasma and they do not reflect the body production of PGI, and TXA,. 2.3-dinor+ketoPGF,, reflects the systemic PGI, synthesis and is the major metabolite of PGl, in urine. ZEdinor-TXB, and ll-dehydro-TXB, are the main urinary metabolites of TXA,. Metabolitcs of PGI, and TXA, have several forms in aqueous solutions at different pHs. In many chromatographic systems, the simultancots presence of the different structures of the solute retiults in doubie peaks, poor peak shape and poor recovery. In the present work, the effects of mobile phase composition and pH on the pc~k shape of prostanoids (mctabolitcs