Adrenaline-induced hypertension in rats.

Rats were given a slow-release depot implantation containing adrenaline (0.33 mumole/kg). Adrenaline was released from the implant, giving a plasma level of 1.0 nmole/liter the day after implantation. Adrenaline-treated rats had elevated blood pressures compared to control rats from 1 day to 8 weeks after treatment. However, 8 weeks after treatment no adrenaline from the implant was found in the plasma, suggesting that at this time factors other than the adrenaline were responsible for maintaining the rise in blood pressure. In rats given metoprolol tartrate (5 mg/kg/day, p.o.), adrenaline treatment did not increase the blood pressure.