Studies with the optically active isomers of the new diuretic drug ozolinone. I. Differences in stereoselectivity of the renal target structures of ozolinone.

The renal actions of the optically active isomers of the new diuretic drug ozolinone were studied by clearance, flowmeter and micropuncture techniques in rats. The levorotatory, but not the dextrorotatory isomer of ozolinone increased urine flow, urinary sodium and chloride excretion and enhanced sodium and chloride concentrations in early distal tubular fluid as checked by in situ microperfusion of Henle's loops. This indicates stereospecificity of the drug's diuretic action. However, both isomers of ozolinone equally inhibited maximal tubular secretion of paraaminohippurate and increased renal blood flow as measured by an electromagnetic flowmeter. Thus, the different renal target structures of ozolinone differ markedly with respect to stereoselectivity.