Glomerular filtration rate and renal plasma flow in patients with essential hypertension before and after treatment with alprenolol.

In 25 patients with essential hypertension, the renal plasma flow RPF), glomerular filtration rate (GFR) and BP have been measured before and after one month's treatment with alprenolol. The patients were divided into two groups according to age. Group 1 consisted of 10 patients with mild hypertension under 35 years of age, group 2 of 15 patients over the age of 35 with moderate hypertension. A markedly greater lowering of BP was measured in group 1 than in group 2. There were no changes in RPF or GFR after alprenolol treatment and no differences in these parameters were observed between the two groups either before or after treatment. Group 1 displayed significantly lower renal vascular resistance (RVR) than group 2 both before and after treatment, and alprenolol treatment resulted in a slight reduction of RVR in group 1, but not in group 2. The difference between the two groups with respect to the antihypertensive effect of alprenolol and the RVR may possibly be due to the fact that the patients in group 2 had more pronounced structural vascular alterations than those in group 1.