Metabolites of the angiotensin II antagonist tasosartan: the importance of a second acidic group.

Described in this paper is the synthesis and pharmacological activity of five metabolites of the angiotensin II antagonist tasosartan (1). Of particular interest is the effect of the additional acidic group of the enol metabolite (8) on activity. As suggested by the structural-activity relationship of other angiotensin II antagonist series, a second acidic group can improve receptor binding activity but decrease in vivo activity after oral dosing.

Pyrido[2,3-d]pyrimidine angiotensin II antagonists.

A series of pyrido[2,3-d]pyrimidine angiotensin II (A II) antagonists was synthesized and tested for antagonism of A II. Compounds with a biphenylyltetrazole pharmacophore and small alkyl groups at the 2- and 4-positions of the pyridopyrimidine ring were found to be the most potent in an AT1 receptor binding assay and in blocking the A II pressor response in anesthetized, ganglion-blocked A II-infused rats. 5,8-Dihydro-2,4-dimethyl-8-[(2'-(1H-tetrazol-5-yl) [1,1'-biphenyl]-4-yl)methyl]pyrido[2,3-d]pyrimidin-7(6H)-one (4a) was one of the more potent compounds in the binding assay and was the most efficacious compound in the A II-infused rat model.

Effect of leukotrienes of renal water excretion.

To investigate the renal actions of leukotrienes (LT), we infused arachidonic acid into the renal artery of anesthetized dogs during systemic cyclooxygenase inhibition (with ibuprofen) alone or in combination with lipoxygenase inhibition or LTD4/LTE4 receptor antagonism. Renal arachidonic acid infusion following ibuprofen alone decreased urine osmolality (945 +/- 143 to 698 +/- 144 mosm/kg; p < 0.01) and increased urine flow rate (0.

Renal vasodilation with acetylcholine but not secretin increases nonnutrient blood flow.

To investigate the fact that, despite its renal vasodilator properties, acetylcholine (ACh) provides no protection against acute renal failure, we measured nutrient (NBF) and nonnutrient renal blood flow (NNBF) during ACh infusion. The effect of ACh and secretin on NBF in the outer and inner cortex and outer medulla using 133Xenon (133Xe) washout with freeze dissection analysis was determined. We then calculated NNBF as the difference between NBF in the entire cortex and outer medulla (133Xe washout) and total renal blood flow (TRBF) measured by electromagnetic flow probe.