Antihypertensive and Antidiuretic Effects of 3-Hydrazino-6-[N, N-Bis (2-Hydroxyethyl) Amino]-Pyridazine (L 6150) in Rats

3-Hydrazino-6-[N, N-bis (2-hydroxyethyl)amino]-pyridazine (L 6150) has been reported as an antihypertensive vasodilator drug. We determined antihypertensive effect of L 6150 for 11 weeks in spontaneously hypertensive (SHR) rats, deoxycorticosterone and salt (DOC) hypertension, and renal hypertension due to clipping (CLIP). The effects of hydralazine (HZ) and ecarazine (EZ) were also determined for comparison. L 6150, HZ, and EZ showed antihypertensive effects in SHR, DOC and CLIP hypertensive rats. These drugs increased heart rate in SHR and DOC rats. In CLIP hypertension heart rate tended to be higher for 9–10 weeks after the treatments. These treatments diminished incidence of the vascular disease in DOC and CLIP. We also determined renal effects of L 6150, HZ and EZ in normal rats. These drugs decreased urine volume, and excretion of osmotically active solutes, Cl, Na, and K for 180 min after bicarbonate saline load. It is concluded that L 6150 is an antihypertensive drug with characteristics of the vasodilator in rats.