The antihypertensive effect of U-0521 (3',4'-dihydroxy-2-methylpropiophenone)

The synthetic catechol, U-0521, (3',4'-dihydroxy-2-methylpropiophenone) is a competitive inhibitor of both tyrosine hydroxylase and catechol-O-methyltransferase. Continuous subcutaneous administration of 10 mumoles per day of U-0521 via Alzet osmotic minipumps to adult male Spontaneously Hypertensive Rats (SHR) reduced blood pressure from 160 mmHg to 125 mmHg. This effect occurred within two days, persisted for the two weeks that the pumps were in place, and reversed gradually upon cessation of U-0521 administration. Similar treatment of U-0521 to normotensive Wistar Kyoto rats (WKY) did not result in a similar hypotentensive effect. Subcutaneous administration of the same dose to juvenile SHRs led to a blockade in the expression of hypertension. After the five week treatment period, the blood pressure of the U-0521 treated animals escalated rapidly to match the saline treated controls. The antihypertensive effect of U-0521 on SHRs also occurred when the compound was delivered by the oral route at the rate of 50 mg/kg/day.